When using the DataPA Excel Add-in in versions of Excel 2003 and before an error is received when connecing to the AppServer.

There error received is:

This means that queries cannot be run.

For Excel 2003 there is an update available from Microsoft which will resolve this error. This is available here:

"Update for Office 2003 (KB907417)"

For versions of Excel prior to Excel 2003 there is not an update available from Microsoft.

.NET 2.0 installs a compatibility policy for both Excel.exe and Word.exe. The compatibility policy prevents loading of CLR 2.0 and causes CLR 1.1 to be loaded into the process unless a fix to OTKLoader.dll has been installed on the machine. After the update is installed CLR 2.0 is unblocked.

However the compatibility policy exists in the registry - so you can remove it although it should be noted that this is NOT an official MS recommendation. However due to bugs in CLR lockback implementation the lockback is getting triggered under the circumstances it is not supposed to i.e. on Office XP and Office 2000 and there is not any other way known to reslove this problem.

The registry key you need to remove (or just rename) is HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\policy\AppPatch\v2.0.50727.00000\excel.exe. We would recommend just renaming this value to excel1.exe so it can easily be reimplemented if required.

The original solution to this problem was posted here: http://social.msdn.microsoft.com/forums/en-US/vsto/thread/2ca664bc-c280-492c-b240-ae06f776803d/