External Access Denied To Update A Config File

Hello,

I'm having an issue with a CLR Stored procedure. Everything works great in a 32 bit environment, I have a CLR SP that updates an xml file stored on a local drive. When I execute the Stored proc it does go and update what I want it to in a 32 bit system. When I run the CLR SP on a 64 bit cluster, I seem to have give the "everyone" group write permissions to my G: drive (which is where the file is located that I'm updating). What security context is this SP running under? I thought it would be either under the SQL Service account (which is a domain user in the local administrators group) or what I'm logged in as when I run it from Management Studio (which is a domain admin, also in the local administrators group). If I have given the local administrators group "Full Control" access to the G: drive, why isn't this enough? Why do I have to give the Everyone group write access?

The security context seems odd to me, it seems like it's not running as either one of those 2 users I mentioned, because if it was, then it should be able to update the xml file.

Any help appreciated. Here's the error I'm getting:

Msg 6522, Level 16, State 1, Procedure usp_XMLWriter, Line 0

A .NET Framework error occurred during execution of user defined routine or aggregate 'usp_XMLWriter':

System.UnauthorizedAccessException: Access to the path 'g:ssisPackagesBuildCalendarandy.dtsConfig' is denied.

System.UnauthorizedAccessException:

at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)

at 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)

at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options, String msgPath, Boolean bFromProxy)

at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share)

at System.Xml.XmlTextWriter..ctor(String filename, Encoding encoding)

at System.Xml.XmlDocument.Save(String filename)

at XMLWriter.StoredProcedures.usp_XMLWriter(String xmlDocPath, String xmlNodePath, String xmlInnerText)

.