Question : DNS Issue?

Dreamhost is hosting our site.  6 days ago they informed us that they were going to change our IP address over the weekend.
The change seems to have propagated everywhere but in our building.
We still ping the old IP address.
We are hosting our own email and we use active directory.
Thoughts?
Dreamhosts says that it is on our end.

Answer : DNS Issue?

Check your internal DNS and the host (A) record for the website.. I think it is pointing to the old IP address... If yes, change it to new IP address and restart the DNS services...