Incorrect DLL Version - DLLs are updated fairly regularly. This will soon become evident should you begin the search for one either on your system or from a third party website. In some cases, if you have the incorrect version installed on your system then this may cause errors. However, most DLLs are backwards compatible. This means that if you install a new version, but another application is calling for an older version you should not experience any problems.
Where errors of this nature tend to occur is when one application installs an older version of a DLL, while an existing application is demanding an older version. These errors are relatively rare, but when they occur, they can be the most troublesome to resolve.