Strange problem in dialing to a certain set of numbers..

[akshayxyz]

Hi,
I have a very peculiar problem. I am not able to call certain numbers, the call just doesn't connect.
I have noticed that those number happen to be office conference(meetingplace) numbers, call center numbers, board lines.
Doesn't matter if its local or ISD.
And when I put my SIM into any other device (I tried with Samsung, motorola, HTC-touch), all those number work perfectly fine.

So I have come to the conclusion that it has something to do with HTC-Diamond or software on the device ( WM6.1 or something).

Any clues/settings?

[akshayxyz]

For others' reference.
I upgraded to ROM version 1.93.720.2 WWE from 1.37 something ( the default ROM that came with the device).

And the problem went away. Now it works fine.