I have an InfoPath SharePoint web browser form which is using digital signatures to sign sections of the form. The digital signature activex controls are installed correctly (when logged on as an admin on the machine). The issue I am having is not with the activex installs (as I can get group policy to install the add-ins and the DSigCtr.dll and DSigRes.dll) as they exist, however when the user (who isn't an admin on the local machine) clicks on the Click here to sign this section I get a SharePoint InfoPath form services error (which I don't get when logged on as an admin). I have checked the loaded add-ins in Internet Explorer and both are active and enabled. If I give the same user local admin rights the pop up to select a signature and verify is displayed.
My question is which other permissions does the user require (I cannot give the user local admin so I have to be specific)? I have used process monitor but have found nothing, I have also looked in the SharePoint logs and nothing is in there as well.
Many Thanks