My apologies.
I'm pretty sure it's the same problem that the others have been having.
Some clever boffin in a office somewhere has decided that a snippet of code from that .DLL has potential to be malicious, or matches in part a known virus.
Your virus checker has read this information and removed/deleted the file accordingly.
Check where your AV quarantines files, and restore it; failing that you will need to reinstall DBPro.
Might be an idea to add the md5.dll to your exclude list in the antivirus to stop it happening again.