99% of the time this is not a problem with the server but a problem with your ASP code.
Launch internet explorer and goto TOOLS > Internet Options
Select the Advanced tab
Untick "Show friendly HTTP error message"
And apply this setting.
Now goto the page or website again and you will see the real error message.
It will show you the line number that your asp code errors at.
Email any time or call 01480 26 00 00 014 80 26 00 00