RTC Automation error

I need your urgent help.

I developed PC2Phone using RTC but when i am trying to call from windows which is not having any SP. i am getting Automation error. But on SP2 or greater than this working well.

Here is my full error:

Run-time error: '-2131885963(80ee0075)'

Automation error

Please help me i will be apricate for ur replies.
Thank You
Abdul

[499 byte] By [Abdullateefkhan] at [2007-12-23]