loop works in 2000 but not in XP

[aalexander2003]

The following loop worked in outlook 2000 but not when i installed it on another computer which has XP

For Each objAppt In colCal
myString = objAppt.Categories
If (myString <> &quot;&quot Then
catList = catList & myString & &quot;, &quot;
End If
Next

The error is on the last line. objAppt is an Outlook.AppointmentItem. colCal is an Outlook.Items.

Any ideas?

thanks,
Ashwin