An audio conference or a video conference fails in Communicator 2007 when you try to invite a new participant to create a multiparty conference

When you try to invite a new participant to create a multiparty conference in Microsoft Office Communicator 2007, the audio conference or the video conference fails. This issue affects the audio conferencing or the video conferencing in the Communicator 2007 client and in the Microsoft Office Live Meeting 2007 client. Additionally, the Audio-Video Conferencing Server component on the Microsoft Office Communications Server 2007 server that is hosting the conference logs an event that resembles the following in the Office Communications Server event log:

Event Type: Warning
Event Source: OCS Audio-Video Conferencing Server
Event Category: (1017)
Event ID: 32011
Date: 01/18/2008
Time: 7:00:53 PM
User: N/A
Computer: Computer name
Description:
A user attempted to connect to a conference, but the INVITE request was not valid. The request was rejected.

This problem occurs because the Communicator 2007 client formats the Session Description Protocol metadata incorrectly when you use a language other than English in the Regional and Language Options dialog box. Therefore, the Session Description Protocol metadata is rejected by the Audio/Video Multi Control Unit (MCU).

To resolve this problem, install the Communicator 2007 update package that is dated April 2, 2008. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

To work around this issue, use one of the following methods.

Method 1

On the client computer, set the language to English in the Regional and Language Options dialog box. To do this on a Windows XP-based computer, follow these steps.

Note Because there are several versions of Microsoft Windows, the following steps may be different on your computer. If they are, see your product documentation to complete these steps.

1. Click Start, point to Settings, and then click Control Panel.
2. Click Date, Time, Language, and Regional Options, and then click Regional and Language Options.
3. On the Regional Options tab, set the language to English (Unites States).

Method 2

On the client computer, change the decimal separator from a comma (,) to a period (.) in the Number box in the Regional and Language Options dialog box. To do this on a Windows XP-based computer, follow these steps.

Note Because there are several versions of Microsoft Windows, the following steps may be different on your computer. If they are, see your product documentation to complete these steps.

1. Click Start, point to Settings, and then click Control Panel.
2. Click Date, Time, Language, and Regional Options, and then click Regional and Language Options.
3. On the Regional Options tab, change the decimal separator to a period in the Number box.

Communicator 2007 formats the Session Description Protocol metadata incorrectly when the current language on the computer does not use a period as the decimal separator. English regional options use the following format for number: Most other languages use comma as a decimal separator.