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yes, those are the instructions that I followed to get the ByteBlaster to show up in the Hardware list originally.
Do you think the ByteBlaster is the problem and not with JTAG, which is giving the error message and which I've never used before ?
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The ByteBlaster is most likely the problem. The error message you see is from a server, i.e., user-space software. That software is failing to communicate with the parallel port driver. The fact that you have to follow convoluted instructions just to get the ByteBlaster recognized under Windows means that Altera put no effort into supporting it. You're better off giving up and getting a USB-Blaster.
You could also run Linux. I suspect the ByteBlaster support there has been unchanged since forever.
Cheers,
Dave