We have the same issue, but we are using VFP 8 SP1. After a long talk with Microsoft, we got the Hot Fix for VFP8 SP1. (It's not freely distributed, you have to contact Microsoft and they will send it to you after signing a new EULA). It completly solve the issue when dealing with real printers. BUT (there is always a but) our PDF tool (eReports) is still reporting the same issue. I hope this information might help you.

>Problem: when printing a report in a vfp application hosted on a citrix presentation server, we get the error message: Error 1958: Error loading printer driver. The printerdriver in question is the citrix universal printer driver.
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>After long search, i found KB909283 to be the problem (http://support.microsoft.com/default.aspx?scid=kb;en-us;909283) . The nasty thing is that the solution (a hotfix) is partially implemented in vfp9 sp1 (the IDE printer not ready message) but not the error loading printer driver problem.
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>Is there anyone who has had this problem and/or does know a solution to this? (native printerdrivers is not an option)