Instant Messenger 4.5 and Exchange 2000

[exchlist]

Title: Instant Messenger 4.5 and Exchange 2000

Hello,
        Has anyone experienced any problems with IM4.5, with the Exchange update (from MS Exchange Website) and Exchange 2000?  I have upgraded two of my machines to IM 4.5, with the Exchange update and now they cannot communicate with each other.  They can send messages to the Admin account, which is using IM 3.5, the version that came with Exchange 2000.  Both of the machines cannot receive messages from anywhere.  Kind of bizarre, anyone  have any suggestions?

Thanks in advance,

Mark

List Charter and FAQ at:
http://www.sunbelt-software.com/exchange_list_charter.htm