Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server."

Question

I have couple of update panels and jquery tabs on page. And also I am loading couple user controls on update panels. After user waited for couple of minutes (not checked the

Answer 1

Had this problem when using AsyncFileUploader in an iFrame. Error came when using firefox. Worked in chrome just fine. It seemed like either the parent page or iframe page was loading out of sync and the parent page could not find the controls on the iframe page. Added a simple javascript alert to say that the file was uploaded. This gave the controls enough time to load and since the controls were available, everything loaded without an error.