Exactly what are the errors? 2 and 11 or -2 and -11 or what?
Try zapping the PRAM - download TechTool 1.21 (freeware) from here
Also be sure to delete the MacOS Preferences as well as Finder Preferences.
Your problem is probably an extension/control panel prob... startup with MacOS All extension set (using extensions manager - hold space bar at startup to access or go to Control Panels), and see if the prob still occurs. If it doesn't, then by process of elimination find the culprit.
If it still does occur, report back here.
Also, exactly what machine are you running? RAM etc? Have you installed anything lately? If so, disable anything to do with that before the trial-and-error approach.
You should upgrade to OS 9.04 - that may well solve the problem.