XWEB: Exchange Server 5.5 Outlook Web Access Generates Errors on OWA Servers with No Daylight Savings Time (296689)

SYMPTOMS

When you open your Exchange Server 5.5 Outlook Web Access (OWA) mailbox the first time and OWA is running on a server where daylight saving time is disabled, you receive error messages when you try to open the Calendar and the Options forms.

The first attempt to open the Calendar form fails altogether. You receive the following error message

Unable to set default formats and patterns

and the previous form is opened again. If you try to open the Calendar form again, it opens, however, the issue reoccurs in the next OWA session.

When you open the Options form, you receive the following error message:

Runtime Error in line 348 of SET.ASP

If you decide not to debug it, the Options form is opened; however, the time zone is set to "(GMT-12:00) Eniwetok, Kwajalein," while most of the other calendar options are left blank altogether.

If you leave the Options form without clicking OK, both issues (Calendar and Options) persist. If you click OK to leave the Options form, the problems appear to be resolved because you have defined a valid "personal" time zone by clicking OK, so OWA does not have to read it from the OWA server for you any longer. However, in most cases, this time zone (GMT-12:00), as well as the other options, are not correct for your time zone, so additional manual changes are required.

This error occurs only in conjunction with mailboxes for which the time zone variable is not yet initialized individually and, therefore, needs to be read from the OWA server. Only the time zone setting on the OWA server is at issue here. The time zone settings of the client and of the Exchange Server computer (if it is different from the OWA server) are irrelevant for this issue.

CAUSE

Each existing time zone is represented in CDO as a decimal value between 0 and 52. The Data Type of this value is "long." If daylight savings time exists for a given time zone, this value assumes that daylight savings time is switched on. A flag called "CdoTmzNoDST" can be used to indicate that daylight savings time is switched off. This flag adds 4000 hexadecimal (16,384 decimal) to the current value of the time zone variable.

However, the Cdohtml.dll and Set.asp files are not prepared to cope with values greater than 52 and 51, respectively, in this area. The limitation in Cdohtml.dll is responsible for the error when you open the Calendar form, while Set.asp is responsible for error when you open the Options form.

The limitation in Cdohtml.dll is fixed in version 5.5.2654.90 and later, while Set.asp needs to be adapted manually by the administrator as described in the "More Information" section.

NOTE:The list of time zone values along with the description of the "CdoTmzNoDST" flag are documented on MSDN in the "Platform SDK" in the "CDO Rendering Library" Reference.

RESOLUTION

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to systems that are experiencing this specific problem.

To resolve this problem immediately, download the fix by clicking the download link later in this article or contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question. The English version of this fix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel. Component: CDO

File name	Version
Cdohtml.dll	5.5.2654.90

NOTE: Due to file dependencies, this hotfix requires Microsoft Exchange Server version 5.5 Service Pack 4.

NOTE: To resolve the issue completely, two steps are necessary:

You need to ensure that Cdohtml.dll is version 5.5.2654.90 or later.
You need to modify Set.asp as described in the "More Information" section.

MORE INFORMATION

The fix in Cdohtml.dll resolves the error when opening the Calendar form only. To resolve the issue with the Options form, the administrator must manually adjust the Set.asp file. Set.asp is located on the OWA server in the following folder:

exchsrvr-root\Webdata\language\Options

Make the following two modifications in Set.asp:

Add code to the AmToIdx(n) function, which filters the "CdoTmzNoDST" flag out of the variable "n" if it is set there.

The modified AmToIdx(n) function should look like the following:
Function AmToIdx(n)
Dim A '1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51
A = Array(-1, 20, 24, 23, 22, 28, 25, 26, 16, 13, 11, 7, 6, 4, 3, 2, 1, 50, 45, 43, 42, 41, 39, 37, 34, 33, 31, 30, 15, 19, 18, 21, 17, 14, 12, 10, 9, 8, 5, 0, 49, 48, 47, 46, 44, 40, 38, 36, 35, 27, 29, 32)
If n > &H4000 Then
n = n - &H4000
End If
AmToIdx = A(n)
End Function
This filter is needed because array A contains 52 elements only, rather than 16,384+x elements. Between lines 404 and 454, there is a list of options that contain the values that AmToIdx will map to. If a given time zone has daylight savings time turned off, the value here should be increased by 16,384 (or &H4000). For example, if daylight savings time is turned off for "Pacific Time (US & Canada); Tijuana," the value in line 408 needs to be increased by 16,384. The original line
"<OPTION VALUE="13">(GMT-08:00) Pacific Time (US & Canada); Tijuana"
should be changed to:
"<OPTION VALUE="16397">(GMT-08:00) Pacific Time (US & Canada); Tijuana"
You can automate the change in step 2 for all or some of these lines by requesting the information if daylight savings time is set on the OWA server, or not from CDO, and changing the value automatically if appropriate. To do so:
1. After the iTimezone value is set (that is, after line 105), add the following lines:
  iCDODSTFlag = 0
  If (iTimezone >= &H4000) Then
  iCDODSTFlag = &H4000
  End If
2. For each time zone in the list, starting in line 404, which is supposed to be covered, you need to include the variable iCDODSTFlag. For example
  "<OPTION VALUE="13">(GMT-08:00) Pacific Time (US & Canada); Tijuana"
  would have to be changed to:
  "<OPTION VALUE="13+iCDODSTFlag">(GMT-08:00) Pacific Time (US & Canada); Tijuana"
  NOTE: The line numbers mentioned above are valid for the original version of Set.asp, which comes with Exchange Server 5.5 Service Pack 4 only. For other versions or modified files, the line numbers may be different.