FKAttend.dll is not a system DLL, it is part of a fingerprint recognition system (and is presumably proprietary to the manufacturer of the system).
As a result, it isn't likely to be in an "obvious place" that the system will search: Start by locating it, copying it to your project folder and adding it to your project so it ends up in your BIN folders.
That way, the system has a better chance of finding it! The rules for DLL searching are here:
Dynamic-Link Library Search Order (Windows)[
^]
If that doesn't work, check your app settings: if the DLL is a 32 bit file and your app is 64 (or vice versa) it could cause a similar problem.