Digital Signature under MOSS

I have asp.net page running under MOSS2007 and there is Access Denied error at signing (signedXml.ComputeSignature()). The code works as normal .net web application but it does not work under MOSS. 



Access is denied.     at System.Security.Cryptography.CryptographicException.ThrowCryptogaphicException(Int32 hr)     at System.Security.Cryptography.Utils._CreateCSP(CspParameters param, Boolean randomKeyContainer, SafeProvHandle& hProv) 

• atou rename database when detach /attach
• Attach Database with Rename(Attash as)
• Are Microsoft® SQL Server® 2014 Feature Pack components compatible with SQL Server 2012
• [DTM_10004] The DTM process terminated unexpectedly.
• create database permission denied in database master
• Microsoft Sql Server 2014 Express and AdventureWorks 2014 Script
• SQL Server Express - Installation Sequence
• Dumb question - SQL Server Express 2014 - where is my "SQL" interface?
• Cannot Generate SSPI Context
• SQL Express usage
• Cannot Export from Sql Server Express 2014 to Access 2016
• Managing SQL 2014 Standard
• SQL 2014 Express and WSUS on Windows 2012 R2
• sql server Migration error
• Install SQL Server 2014 Express in Windows 10
• Suddenly lost ability for client connections to SQL Server Express
• MS SQL Server 2014 fails creating a backup
• Linked server taking time
• Connection pool exceeded error
• Not able to install/Uninstall SQL Server Express 2014