Migrate from windows 2003 to SBS 2011

Hello, this is my first post here on this great forum, i hope someone can help me here.

I am trying to migrate from  windows 2003 sp2 std edition to SBS 2011. I have follow the step by step, and made me a key file and run the migration prep tool, and have also run the config analyzer with out any error.

The sbs say that the source server does not meet the minimum requirements for migration.
when i look in the log file i see this:
[832] 110315.121713.6152: Setup: Setting source OS to Other
[832] 110315.121713.6152: Setup: Running requirement check: MigrationReadyRequirement
[832] 110315.121721.2705: Setup: Caught exception: System.Runtime.InteropServices.COMException (0x800706BA): The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)
   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHRInternal(Int32 errorCode, IntPtr errorInfo)
   at System.Management.ManagementScope.InitializeGuts(Object o)
   at System.Management.ManagementScope.Initialize()
   at System.Management.ManagementObject.Initialize(Boolean getObject)
   at System.Management.ManagementObject.GetMethodParameters(String methodName, ManagementBaseObject& inParameters, IWbemClassObjectFreeThreaded& inParametersClass, IWbemClassObjectFreeThreaded& outParametersClass)
   at System.Management.ManagementObject.GetMethodParameters(String methodName)
   at Microsoft.WindowsServerSolutions.Setup.SBSSetup.RegistrykeyCheck.DoCheck(SourceServerType sourceType, Boolean isRemote, String domainName, String sourceServerName, String userName, String password)
   at Microsoft.WindowsServerSolutions.Setup.SBSSetup.MigrationRequirement.CheckRequirement(SourceServerType sourceType, Boolean isRemote, String domainName, String sourceServerName, String userName, String password)
[832] 110315.121721.2705: Setup:       Error - Run the Migration Preparation Tool on the Source Server - Has Help
[1536] 110315.121721.3095: Setup: Failure: Error - Run the Migration Preparation Tool on the Source Server - Has Help


I have read somewhere that it dont like the clas network we use (10.12.10.xx), but i can find connect from the SBS to the old domain server.
any idea?