Your antivirus program is eating ehsvc.dll
You may need to mark the mabinogi directory as "ignore from scanning", apparently NOD32, AVG, and Codomo have deleted this file before due to identifying the Themida protection on Hackshield consistant with malware. McAfee and Norton have also blocked it in the past from what I've read, but any problem with "ehsvc.dll" is directly hackshield.
Fresh reboot the PC, mark the directory you are installing to as 'safe' in the antivirus program (or turn it off completely if you want to risk it.) Install it, run mabi once to update it and then it should work if this is what the problem is.
IGN: Kisai (Alexina)
Level: 1100+
r1 Spirit of Order
Dan 3 WM
Dan 1 IB
IS,FB,TH, and AR activated
Ideal for Simon, Manus, Muro and others