WebForm_PostBackOptions is undefined after conversion from 1.1 to

[Guest]

I am converting my enterprise solution from VS 2003 (.NET v1.1.4322) to VS
2005 Professional (.NET v2.0.50727).
The entire solution currently uses the following technologies -
Windows Server 2003
Windows Mobile 2003
Windows XP Professional SP2
Windows 2000 Professional SP4
SQL Server 2000
Active Directory
C#
JavaScript
VB.NET
ASP.NET
ASP.NET Mobile
eVC++ 4.0
IE 6.0
Pocket IE

Most of the conversion has gone well, but I have a runtime error that did
not exist in the 1.1 version. It is associated with a Windows Mobile
ObjectList (mobile:ObjectList id="olstTask") When debugging on the desktop in
IE 6.0 (I have *not* yet started conversion testing on the PDA), I click on a
linkbutton in the object list (<asp:LinkButton ID="lbnTask"
CommandName="details" Runat="server"><%# ((ObjectListItem)Container)["name"]
%></asp:LinkButton>)

and now receive a JavaScript error - WebForm_PostBackOptions is undefined.

Any ideas on what might have changed with the Windows Mobile ObjectList
since 1.1 that would cause this?