What type of switch are you using because certain pabx's are capable of manipulating the cdr info. I know that with some systems you can define what to output and the number of digits in the string it may be possible for your switch to strip off the leading 0 from the agent number. Failing that if you are using it for QM what about total recording and setup scheduled recording for the QM aspect?
The two basic principles of Windows system administration:
For minor problems, reboot
For major problems, reinstall