Yahoo Messenger 8 and Vista RC1

I have an issue with Yahoo Messenger 8 and RC1. YM install just fine and
works when logged on as administrator. When a Standard User or Power User
logs on, Yahoo gets an error and closes. (See Below) As soon as I make that
account Administrator it works.

Anyone have an idea on what might cause this?
Thanks, Chris

Log Name: Application
Source: Application Error
Date: 9/9/2006 9:28:32 AM
Event ID: 1000
Task Category: (100)
Level: Error
Keywords: Classic
User: N/A
Computer: Computer
Description:
Faulting application YahooMessenger.exe, version 8.0.0.711, time stamp
0x44f4fd5d, faulting module ntdll.dll, version 6.0.5600.16384, time stamp
0x44f55882, exception code 0x80000003, fault offset 0x00049fb8, process id
0x1494, application start time 0x01c6d41c332cf6dc.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Application Error" />
<EventID Qualifiers="49152">1000</EventID>
<Level>2</Level>
<Task>100</Task>
<Keywords>0x80000000000000</Keywords>
<TimeCreated SystemTime="2006-09-09T14:28:32.000Z" />
<EventRecordID>719</EventRecordID>
<Channel>Application</Channel>
<Computer>Gajedy</Computer>
<Security />
</System>
<EventData>
<Data>YahooMessenger.exe</Data>
<Data>8.0.0.711</Data>
<Data>44f4fd5d</Data>
<Data>ntdll.dll</Data>
<Data>6.0.5600.16384</Data>
<Data>44f55882</Data>
<Data>80000003</Data>
<Data>00049fb8</Data>
<Data>1494</Data>
<Data>01c6d41c332cf6dc</Data>
</EventData>
</Event>