PMDT,
While your subject line mentioned both folders, the content of your post seemed to concentrate on the data directory, so that's what I addressed. The answer is yes, both need to have the right permissions. The funny thing is that the installation instructions
Installing Moodle talk about setting the permissions for the data directory but not the Moodle folder. There is some mention of the latter in
Errors FAQ#Error:_.22500:Internal_Server_Error.22 (Unix-oriented of course!), which until recently was in
Installation FAQ.
I just took a closer look at the first post by RH in the forum discussion I linked to at the end of my previous post,
http://moodle.org/mod/forum/discuss.php?d=77868#p346350, and I think he does a more thorough and probably more accurate job of describing both than I have, so I would refer you to that. The only caveat I would add is that at least one of the other Moodle installation guide links in my previous post suggests, for security reasons, not accepting IIS's default home directory, c:\inetpub\
wwwroot, but putting Moodle in a totally different location, such as c:\moodle. RH mentions this concern also, but he still suggests putting it under c:\inetpub. I don't know whether that matters. So my suggestion is to look at all the links in my previous post; I think each one contains info about IIS that is not in the others, so when you put them all together you have a more complete picture than if you just read one.
RLE