Problems with site

[the_king_dollars]

I have a problem with my site. In some times it tells me "A Bad Gateway" with this message:

The following error occurred:

 The host name was not found during the DNS lookup. Contact your system administrator if the problem is not found by retrying the URL. 
[/B]

  Please contact the administrator.[/QUOTE]
Another error is with the installation of TYPO3 in domain site.mbtg.exofire.net . It is an "Internal Server Error" as it says and it informs me that:
[QUOTE] The server encountered an internal error or misconfiguration and was unable to complete your request. Please contact the server administrator,  webmaster@site.mbtg.exofire.net 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. 
 Apache/1.3.37 Server at site.mbtg.exofire.net Port 80[/QUOTE]
Third problem, maybe not with the site, I can't access my website. Others can but I can't. I think its an error with the ISP. But please tell me the solution to this.

Fourth problem is with phpMyAdmin. It doesn't work for me. It declares that
[QUOTE]Access Denied.[/QUOTE]
So what's wrong?

My account details are:
[QUOTE]Username: tkd
Subdomain: mbtg.exofire.net[/QUOTE]

 

[MicrotechXP]

This is strange. We should let a admin see this.

 

[Derek]

Firewall opened? school computer?

 

[the_king_dollars]

I forgot to note that the site still works. All those problems are temporary (except problem 4) and happen once every two days. So it may happen that you check it now without any problems but after a period it doesn't work again.

 

[Livewire]

3 I'm gunna go with either the isp or the network you're accessing it from - yesterday I couldn't use Firefox or any internet program other than IE to access the internet while anyone else could use whatever they wanted. Network was buggered.

The others I have no idea on. Never used typo3, never gotten a bad gateway (although that might again be the network you're accessing your site from), not on advanced to use phpmyadmin yet (although the last time I had that error on my localhost server I had typoed my database name).

 

[the_king_dollars]

I uninstalled TYPO3, so I got rid of problem 2 (Internal Server Error). But the others are still common problems that happen to my site.
Anyone got an idea?
P.S. As for the third problem (ISP problem), I know that it is either with my ISP or my computer's firewall. The question is, does anybody know how can I fix it?