Unable to add a Web Part Page to Pages document library in WSS 3.0

I am unable to Create a new Web Part Page in the Pages document library of 开发者_如何学Gomy site collection. It shows the following error:

An error has occurred on the server.

Please help, where to start looking for the cause ?

EDIT: I get the following entries in the 12\Logs folder:

Timestamp Process TID Area Category EventID Level Message Correlation 06/28/2011 13:12:35.07 wsstracing.exe (0x15E4) 0x107C ULS Logging Unified Logging Service 8gsv Monitorable perfmon disabled for this process

06/28/2011 13:12:35.07 wsstracing.exe (0x15E4) 0x107C ULS Logging Unified Logging Service 8wsv High ULS Init Completed (wsstracing.exe, ONETNA~1.DLL)

06/28/2011 13:12:35.07 wsstracing.exe (0x15E4) 0x1748 ULS Logging Unified Logging Service 5152 Information Tracing Service started.

06/28/2011 13:15:29.90 OWSTIMER.EXE (0x0998) 0x0E44 Windows SharePoint Services General 0 Medium Entering MRU trim routine.

06/28/2011 13:15:29.90 OWSTIMER.EXE (0x0998) 0x0E44 Windows SharePoint Services General 0 Medium Initial table size: 0 in 0 entries

06/28/2011 13:15:29.90 OWSTIMER.EXE (0x0998) 0x0E44 Windows SharePoint Services General 0 Medium Final table size: 0 in 0 entries

06/28/2011 13:15:29.90 OWSTIMER.EXE (0x0998) 0x0E44 Windows SharePoint Services General 0 Medium Exiting MRU trim routine.

I am able to create new Sites though.

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I'd start by disabling the friendly errors, you do this by opening the web.config and modifying the line…

<SafeMode MaxControls="200" CallStack="false"…

to…

<SafeMode MaxControls="200" CallStack="true"…

You will also need to set custom errors to 'Off' .

<customErrors mode="Off"/>

When done with that we can start narrowing your problem!

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You have to do the same in Web.config under Layouts directory, as CreatePage.aspx is a layout page.

Also, you should look at the logs under 12 hive. Even if you are seeing custom error on screen, actual error will get logged in logs folder. You should also check Event Viewer (Application Events) for any application error that might have occurred.