Any
PHP program that is missing required files will have problems if not FTP'd completely and correctly. If the file was missing, as you claimed, then there was an obvious error somewhere, and not with
PostNuke.
Does
PostNuke have some problems? Yes - its is, after all, in a pre 1.0 stage. Legitimate bugs, from my experience, are addressed quickly and/or fixes outlined on this forum.
Good luck with whatever you choose.
I've used many
CMS's, and they ALL have issues at one time or another - not usually becuaes of their own code, but the hosting hardware,
OS, and conflicts, mis-configured or mis-compiled servers and
PHP or mysql, etc.
If you just got into
PHP, then you'll soon come to realize that many open source
PHP programs are in evolving stages - there will always be some tweaking and such to make it work perfectly, or look exactly how you like, etc.
Good luck,
UHEweb