Getting rid of Sharepoint Site HTTP 403 Error - Forbidden or Access Denied error - Part 3

Some other considerations:
Here I am assuming that the sharepoint is installed at standard location "C:\Program Files\Common Files\Microsoft Shared\web server extensions\12".

ISAPI-where the web services should be placed
TEMPLATES\CONTROLTEMPLATES - where usercontrols are placed
wpresources(under ur webapplication directory)- where webpart resources are placed.

all these directories have "ServerName\Users" group added with "Read","Read&Execute" and "List folders" permissions. this group contains IIS guest account, IIS process account and ASPNET account and othe users for server. So by default, all authenticated users can access the resources under these directory but the Bin directory under your Web application doesnt have this group added so be careful if u are adding any resource that requires all users to have Read or Read&Execute permissions.