o_stl.dll is a module DLL file. DLL files can be used by more than one program thus allowing for more free space on your computer. Only part of a code is contained within a modular file. Error codes from these types of files typically mean that it is not necessary for your computer.
DLL files are commonly the result of the inaccurate installation or deletion of programs. They can collect on your hard drive, getting in the way of your computer completing the task that you would like it to complete.
Sometimes DLL files are malicious files created to steal your computers information or even your keystrokes. It is in your best interest to use ZookaWare PC Cleaner to clean your systems registry and rid your computer of these harmful files today. There’s nothing to lose with their money-back guarantee.