winlogon runtime error 5

When logging on to xp home edition I get a dialog box
that says Runtime Error 5 at xxxxxxx...it comes up
twice. if i click ok on the first one then click ok on
the second box the system like loops and goes through the
routine again...if I only click ok on the first dialog
box and leave the second alone the system runs ok but I'm
left with the second dialog box...it seems a problem has
developed in a script that is run during logon...but I
can't find a way to get any more clues as to where the
actual problem is...seems to be somewhere in winlogon or
in password authentication maybe? Any help would be
appreciated...