Help - Errors after changing to FastCGI and eAccelerator

Since changing over to FastCGI and eAcclerator, my site has run into multiple problems:

Problems:

Have you recompiled Apache with all the necessary PHP extensions?

Have you re-checked the folder permissions?

Where can I find a list of the necessary PHP extensions so I can send it on to my hosting provider who did this for me?  I'm using HostForWeb. I figured they would know what they are doing since they are Dolphin certified, however, I'm not so sure at this point.

Folder permissions are correct in Admin panel.  However, the photos issue seemed to resolve itself after reducing  flash / modules / photos / files permission to 755 from 777. Does that make sense?

I still can't join the site through join.php

Note:

Go to the following folder on your server.

plugins\htmlpurifier\standalone\HTMLPurifier\DefinitionCache\Serializer

In that folder you will see 4 other folders.

CSS
HTML
Test
URI

Make sure all of those folders are writable. Mode 777

Then go into each of those 4 folders and delete any files found in them.

Then empty your cache and try again.

Related to a similar issue in this post with the HTMLPurifier

http://www.boonex.com/unity/forums/#topic/Permissions-Error.htm

http://www.boonex.com/trac/dolphin/wiki/DolTech

Thank you both very much for your expertise. My site is now working again