Hello, This concerns a known bug in the frame_setlineno() function for Python 2.5.x and 2.6.x (maybe in earlier version too). It is not possible to use this function when the address or line offset are greater than 127. The problem comes from the lnotab variable which is typed char*, therefore implicitely signed char*. Any value above 127 becomes a negative number. The fix is very simple (applied on the Python 2.6.1 version of the source code): --- frameobject.c Thu Oct 02 19:39:50 2008 +++ frameobject_fixed.c Fri Dec 05 11:27:42 2008 @@ -119,8 +119,8 @@ line = f->f_code->co_firstlineno; new_lasti = -1; for (offset = 0; offset < lnotab_len; offset += 2) { - addr += lnotab[offset]; - line += lnotab[offset+1]; + addr += ((unsigned char*)lnotab)[offset]; + line += ((unsigned char*)lnotab)[offset+1]; if (line >= new_lineno) { new_lasti = addr; new_lineno = line; It would be nice to fix it for Python 2.5 and above, in order to have a proper MSI installer for Windows. Best regards, Fabien Bouleau DISCLAIMER: This e-mail contains proprietary information some or all of which may be legally privileged. It is for the intended recipient only. If an addressing or transmission error has misdirected this e-mail, please notify the author by replying to this e-mail. If you are not the intended recipient you must not use, disclose, distribute, copy, print, or rely on this e-mail.