[MonoDevelop] Monodevelop install problem on mac

[Paul Varnish]

on a MacBook running Mac OSX 10.5.8
have downloaded and installed
Mono 2.6.7 (Intel)
and
MonoDevelop 2.4.2

On launching monodevelop, I get a failure to start....
MonoDevelop failed to start. The following error has been reported: An  
exception was thrown by the type initializer for  
MonoDevelop.Projects.Dom.Parser.ProjectDomService.
with detail as follows
System.TypeInitializationException: An exception was thrown by the  
type initializer for MonoDevelop.Projects.Dom.Parser.ProjectDomService  
---> System.UnauthorizedAccessException: Access to the path "/Users/ 
paulvarnish70" is denied.
   at System.IO.Directory.CreateDirectoriesInternal (System.String  
path) [0x00000] in <filename unknown>:0
   at System.IO.Directory.CreateDirectory (System.String path)  
[0x00000] in <filename unknown>:0
   at System.IO.DirectoryInfo.Create () [0x00000] in <filename  
unknown>:0
   at (wrapper remoting-invoke-with-check)  
System.IO.DirectoryInfo:Create ()
   at System.IO.Directory.CreateDirectoriesInternal (System.String  
path) [0x00000] in <filename unknown>:0
   at System.IO.Directory.CreateDirectory (System.String path)  
[0x00000] in <filename unknown>:0
   at System.IO.DirectoryInfo.Create () [0x00000] in <filename  
unknown>:0
   at (wrapper remoting-invoke-with-check)  
System.IO.DirectoryInfo:Create ()
   at System.IO.Directory.CreateDirectoriesInternal (System.String  
path) [0x00000] in <filename unknown>:0
   at System.IO.Directory.CreateDirectory (System.String path)  
[0x00000] in <filename unknown>:0
   at System.IO.DirectoryInfo.Create () [0x00000] in <filename  
unknown>:0
   at (wrapper remoting-invoke-with-check)  
System.IO.DirectoryInfo:Create ()
   at System.IO.Directory.CreateDirectoriesInternal (System.String  
path) [0x00000] in <filename unknown>:0
   at System.IO.Directory.CreateDirectory (System.String path)  
[0x00000] in <filename unknown>:0
   at  
MonoDevelop 
.Projects 
.Dom.Parser.ProjectDomService.GetDefaultCompletionFileLocation ()  
[0x00000] in <filename unknown>:0
   at MonoDevelop.Projects.Dom.Parser.ProjectDomService..cctor ()  
[0x00000] in <filename unknown>:0
   --- End of inner exception stack trace ---
   at MonoDevelop.Ide.IdeApp.Initialize (IProgressMonitor monitor)  
[0x00000] in <filename unknown>:0
   at MonoDevelop.Ide.IdeStartup.Run (System.String[] args) [0x00000]  
in <filename unknown>:0

In itself, not so strange and somewhat self-explanatory.
But paulvarnish70 is not my mac user name. It's paulvarnish.
paulvarnish70 is an old user that I have long ago deleted.
Any idea why it might still be hanging around ?

Thanks for any help...
Paul.