I've tried to run Lertap and get a message "Whoopsie! An important file, KeyLib32.dll or KeyLib64.dll, may be missing from the system32 folder."
Solution:
The keylib32.dll, keylib64.dll, and lertap2.lf files should have been installed in your Windows/System directory when you ran the Setup program that was in the 30-day trial of Lertap 5 that you downloaded. If you still got this message, download this zipped file and unzip it into your "Windows/System" directory. Depending on what version of Windows you are running, this directory may be called "WinNT/System32" or something similar.
Source: Assessment Systems Corporation technical support