What sort of a 7206 do you have ? Is it a VXR model ?
The 72xx non-VXR models only support the following:
NPE-100, NPE-150, NPE-175, NPE-200, and NPE-225
The 7206VXRs, on the other hand, support all NPE models.
Hope that helps - pls rate the post if it does.
Paresh