Hi
Per your description, I do not verify what your topology is, and what the deployment procedures are. Because there is a recommended sequence of steps that you must perform 2007 UM environment and in your OCS2007 environment to correctly deploy Enterprise Voce and Exchange 2007 UM. Below are some suggestions for you to make a troubleshooting.
1. Sipeps.dll is in the exchange server. So you should check it firstly on your exchange server. Confirm the Exchagne2007 UM server role was configured properly. You can refer to below link:
http://technet.microsoft.com/en-us/library/bb676409.aspx
2. Run the ocsumutil.exe command that creates the contact objects for subscriber access and for the auto attendant. It also validates that there is a location profile name whose name matches the FQDN of the Exchange UM dial plan. Per my experience, it is pre-requisite. You can refer to below link:
http://technet.microsoft.com/en-us/library/dd425090(office.13).aspx
3. About how to configure UM on Microsoft Exchange to work with OCS, you can refer to below links:
http://technet.microsoft.com/en-us/library/dd441297(office.13).aspx
http://technet.microsoft.com/en-us/library/dd425191(office.13).aspx
http://technet.microsoft.com/en-us/library/dd425192(office.13).aspx
Hope this helpful!
Regards!
