Attachment size error

[mk craig 42]

Everytime I try to upload an attachment larger than 100kb, it gives me this message:

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, webmaster@mywebsite.com and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

These are my settings:

Server Type Linux
Web Server Apache (cgi-fcgi)
PHP 5.3.8
PHP Max Post Size 8.00 MB
PHP Maximum Upload Size 128.00 MB
PHP Memory Limit 128.00 MB
MySQL Version 5.1.56
MySQL Packet Size 1.00 MB

I've spoke to my hosting company and they said that the problem seems to be coming from my side.. they asked me if I had any inner vBulletin settings, and I have none that I know of.

I deleted the php.ini file with the settings on, but no luck, I try to use .htaccess to change this (as hosting company said I can edit it via .htaccess) but I get the same message as above when I add this into there:

php_value upload_max_filesize 20M
php_value post_max_size 20M
php_value max_execution_time 200
php_value max_input_time 200

Any help would be great.. I'd be more than happy with an upload size of 8MB
Thanks.