Another welcome, sorry I didn't see this sooner. I'm not aware of any listing of errors, either. As wanna play said, if you've got a question about a specific study, just ask. There's a couple of people on the forum who have been through that whole book and can probably help - they've even made some backing tracks if you're interested. Also, most everything just gets posted in the "blues" section of the forum, even the "Jazzin' the Blues" stuff, and I think this jazz section of the forum is largely abandoned. You'll get more responses if you post in the "blues" section.
I don't think there is an errata for either of the books. Just ask about errors on either forum - you will surely get an answer quickly. There are few typos here and there, the ones I've come across have mostly been easy to correct from listening the audio recordings.
I've always intended to create an errata on this site. I have scores of slips of paper with corrections scattered around my office. Time to pull them all together. If any of you are interested, I'd much appreciate seeing what you have noticed. TimD2112, let me know what you found. JG