Getting Forbidden Access Message

I have been adding links to a links page on our site, and most go ok, but I have come across 2 that cause an error to be displayed when submitting page edit in ACP>IM Portal>Block Management.
I am adding the 2 following:
<a>Party Poker Bonus Codes</a>
<a>Vig-rx</a>
The error I get:
Forbidden
You don't have permission to access /forum/admin/admin_blocks.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
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Apache/1.3.34 Server at http://www.aaquacks.com Port 80
I don't know why, but these 2 seem to trigger something. I have been able to add other links since these errors, but if I go and try them again, the error comes again. So I would have to think there is an issue with those 2 links.
I am adding the 2 following:
<a>Party Poker Bonus Codes</a>
<a>Vig-rx</a>
The error I get:
Forbidden
You don't have permission to access /forum/admin/admin_blocks.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
--------------------------------------------------------------------------------
Apache/1.3.34 Server at http://www.aaquacks.com Port 80
I don't know why, but these 2 seem to trigger something. I have been able to add other links since these errors, but if I go and try them again, the error comes again. So I would have to think there is an issue with those 2 links.