Hosting issue on hostgator

Question

I uplaoded a asp.net website on hostgator shared server when I submit data through a form it show following error  "

Server Error in '/' Application.

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Security Exception

Description: The application attempted to perform an operation not allowed by the security policy. To grant this application the required permission please contact your system administrator or change the application's trust level in the configuration file.

Exception Details: System.Security.SecurityException: Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.

 

"

 

 When I contact hostgator they ask you website required full trust but hostgator shared server only give medium trust level.

 

I change trust level in config file but error not fixed yet.

 

Anyone help me is this regard?