No. The amount of consecutive incorrect lock codes is not limited and you cannot lock your Nokia device permanently by entering wrong lock codes. However, if you enter the wrong lock code for 5 consecutive times, the device is locked for 5 minutes during which time it doesn't accept any codes, not even the correct one.
Note that some applications may add security measures of their own if an incorrect lock code is given too many times. For example with Mail for Exchange the administrator can define that all the data in the device is deleted when a maximum number of lock code retries is reached. The device may show in this situation the following warning message:
Incorrect lock code. One attempt left before data is deleted.
If a wrong lock code is still given after the above warning, the device is reset and all the user data is wiped out.