Google check out error

try to setup set the Google checkout but get error when i click on edit.
can some one help me out.
here is the error message


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=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[SecurityException: Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.]
   System.Security.CodeAccessSecurityEngine.Check(Object demand, StackCrawlMark& stackMark, Boolean isPermSet) +0
   System.Security.CodeAccessPermission.Demand() +59
   System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy) +684
   System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share) +114
   System.Configuration.Internal.InternalConfigHost.StaticOpenStreamForRead(String streamName) +80
   System.Configuration.Internal.InternalConfigHost.System.Configuration.Internal.IInternalConfigHost.OpenStreamForRead(String streamName, Boolean assertPermissions) +115
   System.Configuration.Internal.InternalConfigHost.System.Configuration.Internal.IInternalConfigHost.OpenStreamForRead(String streamName) +7
   System.Configuration.Internal.DelegatingConfigHost.OpenStreamForRead(String streamName) +10
   System.Configuration.UpdateConfigHost.OpenStreamForRead(String streamName) +42
   System.Configuration.BaseConfigurationRecord.InitConfigFromFile() +437

You need to ensure the proper permissions configured. Give read/write permissions to "google" folder and Google\google_log.txt file

Similar problem!

Set permissions on /google/.../ no luck!

Also reset permissions on "Administration" directory -- not sure if this is necessary? But there is a GOOGLE sub-folder in there as well

Log error:
An error occurred loading a configuration file: Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed. (machine.config)

Any advice??

That's a known issue. Configuring google checkout requires full trust.

P.S. But you can manually set required values for GC in your database (Nop_Setting table).