The error 5 means that something is still preventing the drive to be locked for exclusive use which is required for the Read+Write+Read test. Not sure, but there is still an open file/folder or something similar which could prevent it.
Yes, in this case, booting from a Live PE Windows is a good idea: you can use Hard Disk Sentinel Pro Portable under that, to perform the disk testing.
Sorry for the troubles, but yes, the HDK file will surely not work: it is related to a completely different installation. In order to register/activate the Pro Portable version, you'll need to use the 15 digit license code again (not the HDK file).
Personally I recommend to prepare, register, activate Hard Disk Sentinel Pro Portable before booting from that live Windows.
Please refer to:
How to use Hard Disk Sentinel Pro Portable:
How install on a different PC in general (which describes why the HDK file will not work):