Did the Programming Editor work before you installed VS 2008 ?
Have you used Find Files to see if it is actually on the disk and where ?
AFAIUI, comctl32.ocx would be installed with the Programming Editor if it did not already exist so it sounds like it's not been installed properly or perhaps the BAS805.exe has somehow been corrupted during download.
5.2.0 BAS805.EXE is 30,405,982 bytes on my system
5.2.1 PATCH521.ZIP is 9,384,712 bytes on my system
First suggestion would be to uninstall Programming Editor, re-download Programming Editor and re-install again. Maybe uninstall VS2008. In the worse case, re-install Windows and install Programming Editor frst, get that working then start adding other things.
I have XP SP2, VS2008 and Programming Editor 5.2.1 all co-existing without any similar problems.