The abc.dll file is associated with Actuate Reporting System, a piece of software that is integrated into a number of programs. As with any dynamic link library, if the file has been moved or corrupted, it can generate registry errors.
There is also the possibility that a Trojan (a malicious file pretending to be something else) might be masquerading as this legitimate file, so if you get an error involving this file, it is a good idea to clean your registry.
Cleaning your registry is not a task for the faint of heart. Even Windows experts hesitate to edit the registry without absolute certainty of the changes being made. If you want to be certain, clean your registry with ZookaWare PC Cleaner, the registry cleaner. ZookaWare PC Cleaner will scan your registry free, checking for errors that will slow your computer. Scan regularly to keep your computer running quickly and error-free.