A PostScript error offending command: MSTT<####> Undefined (with <####> being a four-digit number) points to the RIP of the printer running out of virtual memory. This is a known error when using the Microsoft Windows PSCRIPT.DRV driver.
Microsoft Technote KB103735 provides the following information:
Microsoft Windows downloads TrueType fonts to a PostScript printer with the MSTT#### naming scheme. If the printer runs out of memory, it may drop fonts, causing the error to occur when the font is called again in the print job.
To prevent this problem, first make sure that the virtual memory setting in the Options > Advanced Options dialog box of the Windows PostScript driver is set correctly for the amount of virtual memory available in the printer. Microsoft includes a test file with Windows that prints a suggested memory setting for the printer. Copy the TESTPS.TXT file to the printer from the Windows SYSTEM subdirectory. For example, if Windows is installed in the directory WINDOWS and the printer is on port LPT1, type the following at the MS-DOS command prompt: copy c:\windows\system\testps.txt lpt1: