Ok, read that and tried:

$douser = GetObject("LDAP://cn=" + $UserName + "," + $LDAPpath)
If @ERROR
MessageBox(@ERROR, '1')
EndIf
MessageBox("LDAP://cn=" + $UserName + "," + $LDAPpath,'2')
$douser.msNPAllowDialin=1
$douser.SetInfo
If @ERROR
MessageBox(@ERROR, '3')
EndIf


Messagebox 1 never appeared - good
Messagebox 2 gave the correct string - good
Messagebox 3 gave error = -2147352567 which means The storage control block is invalid.

Feel I'm possibly doing something wrong setting the radio button value but not sure what.

Any clues would be appreciated.

Thanks