Trying to change owner of account on CRM 4.0 using a plugin - plugins

Question

I am creating a plugin for Microsoft Dynamics CRM 4 that will change the owner of the account entity according to the value of another lookup field. Now I have managed to get the GUID of the user that will be acting as the 'Owner' of the account. So far so good.
The problem arises when I try to change the owner. I am trying to use AssignRequest but it is not working. When I try to execute the request I get a SoapException on the C# Debugger, and the webservice outputs a dialog stating:
"The requested record was not found or you do not have sufficient permissions to view it"
Below is the code I am using:
TargetOwnedAccount target = new TargetOwnedAccount();
SecurityPrincipal assignee = new SecurityPrincipal();
assignee.Type = SecurityPrincipalType.User;
assignee.PrincipalId = context.InitiatingUserId;
target.EntityId = ownerGuid; //this is the GUID I am retrieving from the other lookup field
AssignRequest assign = new AssignRequest();
assign.Assignee = assignee;
assign.Target = target;
AssignResponse res = (AssignResponse)crmService.Execute(assign); //this is where i get the exception
I hope I haven't missed anything.
Any help would be much appreciated :)
Thanks

Answer 1

Ok i managed to solve this finally. It had been staring directly at my face :P
I was entering the wrong ID's at the wrong place. I needed to set the 'assignee.PrincipalId' to the 'ownerGuid' and then set the 'target.EntityId' to the current account id. The new code is as follows:
TargetOwnedAccount target = new TargetOwnedAccount();
SecurityPrincipal assignee = new SecurityPrincipal();
assignee.Type = SecurityPrincipalType.User;
assignee.PrincipalId = ownerGuid; //this is the GUID I am retrieving from the other lookup field
target.EntityId = ((Key)entity.Properties["accountid"]).Value;
AssignRequest assign = new AssignRequest();
assign.Assignee = assignee;
assign.Target = target;
AssignResponse res = (AssignResponse)crmService.Execute(assign);
Cant believe i spent 8 hours yesterday looking at it and then today I realised immediately :P