Something on your computer is preventing Exam4 from installing correctly.
The mostly likely program is your security software. In some cases AOL DataMask is the culprit and should be uninstalled.
- First uninstall the Exam4 software you already have installed.
- Then disable your security software and re-download, then install Exam4.
- Run a practice exam.
- Re-enable your security software and try another practice exam.