Permission denied when I try to create a folder

When I try to create a folder in ASP, the code sometimes fails, with Firefox saying

Microsoft VBScript runtime error '800a0046'
Permission denied
/admin/exit.asp, line 34

'delete and recreate user folder ---------------------------------------------
If objFSO.FolderExists(Server.MapPath("../users/" & Session("username") & "/")) = True Then objFSO.DeleteFolder(Server.MapPath("../users/" & Session("username") & "/"))

'------------------------------------------------------------------------
'this is the line giving me the trouble, according to the browser ------------------------------------------
Set objFldr = objFSO.CreateFolder(Server.MapPath("../users/" & Session("username") & "/"))

'-------------------------------------------------------------------------

Set objFldr = Nothing

It fails about 1 in 4 times. Can anybody help please?

 

Thanks - I used a kludge

In the end I thought, never mind createfolder, I'll just use copyfolder from an empty directory to a new one!