With PSQL v9 Workgroup Engine on Vista, we noticed a status code of 8520. This was caused by Windows Vista limiting all users to Standard user permissions, regardless of whether or not they are logged in under an administrator-equivalent account. This was fixed for v10.
The best answer for PSQL v10 comes from here:
http://www.pervasive.com/library/docs/psql/10/whatsnew/whatsnew-2-03.html
If a user starts the Workgroup Engine or Cache Engine in a Terminal Services session or in a multiple-user environment where fast-user switching is used, other users on the system cannot access that engine nor can they start their own copy of the engine.
Status code 3032 results if a second user attempts to access another user's engine through the transactional interface.
If it is desirable to have multiple local users accessing a local engine, install the Workgroup or Cache Engine as a service. That way, the engine is already running before the first user session starts.
We can’t offer a recommendation for turning UAC On or Off. The only know UAC issue with v10 is with installations taking twice as long.
http://www.pervasive.com/kb/kb.asp?fx=getdetails&solid=00018005&title=Known%20issues%20for%20Pervasive%20PSQL%20v10