Component stop working after upgrade

Hi,
I build a com object (dll) in vb6 6 months ago. The component was build using nt4 and was installed on a nt4 server (the component it's used on asp pages and by other vb components) Everything worked fine until friday when we upgrated the machine where the component was installed to W2000 server and SP2. Now everywhere on that machine I receive error that "ActiveX cannot create object"
In the original code the component was instantiated with CreateObject method (this is the line where I receive errors) I run some quick changes and I found that if I instantiate with New I don't receive any error, but I receive a "Type mimatch" error later.
Any ideea of what can I try to fix this.
What is the diference bettween CreateObject and New?
The dll is not used in transactions.

Thank you,

Sorin

Jim,

Thank you for your answer.
I did unregister the component and register it again and the problem was solved. The component is working normally.

Thank you,

Sorin