custom web part causing access denied to all but sharepoint admin

[PushCode]

I have a publishing site and one of the pages is throwing an access denied error to all users, except for the sharepoint administrator. This error only occurs if the custom web part is on the page. If I remove the custom web part, all users can access the page without error.

How can I troubleshoot this kind of thing?

 

[dinger2121]

what does the custom web part do?

 

[PushCode]

It Runs a few queries and checks for Sharepoint users that are in specified groups.