Our code was created a decade ago; current version uses PB11.2 and the CynergySystems EAF4 which only works with EAServer 5.5 and below. Years ago CynergySystems abandoned their EAF, so in order to move ahead to EAS6 we would have to re-write the EAF Framework ourselves. ( Instead of doing that, we chose to switch to ASP.NET ) However, our secure website still uses our original PB code which was working well; the problem I've described started occurring when the secure website became much more popular, with many more hits than we had originally experienced. We still plan to re-write the site with ASP.NET, but, for the moment, this recurring PDF generation failure is a genuine PITA as the server needs to be restarted to clear the problem, which annoys our customers big time.
AS far as going to PB12.6, we used it to create .NET web services (hosted on IIIS) since we had the datawindows all ready, and could re-use them. We discovered some interesting (and annoying) bugs, but we managed to create .NET versions of our old PowerBuilder code in the end. I suppose we could try to generate the EAServer client code with PB12.6 (classic mode); I'll have to discuss that option with Herb.
I am currently trying a different option, that is, to create the PDF on the IIS7.5 Application Server, and to just go fetch it using the file system (instead of having it returned in a byte array).