Error on save Field Permission in custom list, SharePoint 2010 Enterprise

Dec 12, 2013 at 9:39 PM
Hi

I receive this error after save field permission settings for my list, Please help me. this is an emergency error.

Operation is not valid due to the current state of the object.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: Operation is not valid due to the current state of the object.
Dec 13, 2013 at 3:20 AM
1) hi, this error message is not enough for me to locate the problem. please modify the web.config, make the detail error show.
or if this is the detail message, can you find some other log message by windows log or SharePoint trace log?
2) does this error happen in the field permission setting page?