IPB is what the TCH forums run on and can handle lots of users.
I've used both IPB and phpBB. phpBB is plagued with constant security updates. It's a very popular choice for a BB so it's attacked most frequently.
If you have modded your forum heavily you probably don't want to use the cPanel upgrade.
You would be better off getting the files directly from phpBB and updating your site manually.
As Paul said, there was probably something in the original .htaccess file conflicting with what Wordpress was creating.
Anyway, glad I could help you get it sorted out.
Do the following in cPanel
Open the file manager
Go to your "blog" folder
Create a new text file
Give it a name of .htaccess
Give it permissions of 644
Edit the file you just created
Copy/Paste your permalink strcuture into it
Save your changes
That should be all you need.
Welcome to the forums.
cPanel is the site adminstration panel for your site. Same place you create email addresses, subdomains, etc...
Are you hosted here?
Sorry I have to ask. Which .htaccess file did you update? The one in your public_html folder or the one in your blog folder? It should be the .htaccess file in the blog folder.
Welcome to the forums
I would recommend that you set up an FTP account for people to upload the files to them. Then they would FTP them to their machines.
It's possible to send that large of a file through email but not practicle.