I had a similar issue when trying to install INPA on the laptop using the very same modified VAG KKL lead.
My issue resolved itself when I found out that the lead actually was using Com 4 when connected,
not Com 1 as selected during INPA installation.
Sorry if I'm "teaching my Grandma to suck eggs" here but if you go to:
System Information on the laptop
- select Hardware Tab
- click on Device Manager button, the computers devices now are listed.
- now click the + on the "Ports (COM & LPT) it will now expand to show all the port details, now plug in your Vag Com lead into the USB port and see if it updates its Com number.
If it does you have to select this Com number when reinstalling INPA, or IIRC you can alter some info in one of the Eidebas files, but I'm not 100% sure which one!!!
Again my apologies if you've already verified this.