ZXP 7 - Can not register ZMotifPrinter.dll in Windows 7


I have downloaded the sample codes for ZXP 7 printer for Visual Basic.Net. I tried to register the PrinterSDK as per the instructions from readme.txt file but unable to register it. Below is the error message that I get whenever I try to register. Please let me know any support to register this dll successfully. This file is saved under D:\xxx\xxxxx\VBZmotifSample