Generally we recommend around 200,000 models but this depends mainly on the amount of physical memory as Spectrum 9.x is all 32bit and therefore will have a max ceiling limit of around 3.7gb on Linux or about 2.8gb on Windows unless you enable the /3g switch to use memory reserved from the Kernel to the SpectroSERVER process.
220,000 models generally is the upper limit.
I have seen some customers reach as many as 400,000 models, but there were many performance problems and the SpectroSERVER could crash out of memory as the SpectroSERVER process was at the very limit of 3.7gb on Linux OS.
The error message that you are seeing is most likely not due to the number of models but is more of a problem with Report Manager. The very last hotfix for 9.2 was h13 and it resolved many of the problems, but I have checked and it is no longer available on our FTP site.