Error: Invalid Field Name being experienced with DI-API add-on

We are receiving the following error "Error: Invalid Field Name" when running an add-on in our customers database.

The add-on was developed and compiled against a 2005A SP01 PL31 database but the customer is running it on 2005A SP01 PL36.

During testing we found that the add-on would not produce the above error for some users and not others.

We were able to resolve this for some users by deleting the SM_OBS_DLL folder from the %TEMP% folder.

However, for other users this did not work, yet if we deleted their windows profile the add-on did work.

This suggests the problem may be caused by some kind of caching that SAP Business One or the add-on is performing within the users profile.

We have verified that the add-on does not store anything in the users profile or registry and have also verified that the SAP profile and registry settings between a working user and invalid one are consistent.

Does anyone have any pointers or ideas on what else we could look at or try to isolate the problem.

Cheers,

Sean