Eric,

 

Please try the steps below:

 

1. Create a simple aspx and make sure it works on your server

 

2. Start to add contols to the page and find out which control causes the problem.

 

For example, if you have 10 controls, you can separate it into two groups.  And find out which group cause the problems.

 

Again, separate this into two groups again... until you find out which control causes the problem.