I had the operand issue on the last page on my watermarked pdf from drivethrurpg. I use Adobe Reader X. I've switched to SumatraPDF (thanks for the hint above) and I'm not getting the error any longer. I had re-downloaded Legend core when I received an update email advisory, to no avail. That pdf also had the operand issue. It only is missing the OGL and back cover when that operand error occurs.
Anyhow, as to the book, awesome! I love the rulesystem over the ages (since Runequest 2nd Edition way back in 1979), Stormbringer in '81, and it's newer derivations/iterations via Cthulu and others. I think Legend core represents a very clean version of the system. By that I mean it is easy to follow, and supplies good examples throughout the book, not just in one part of the book. Thanks for putting this out as OGL content, and for that matter at a steal of a price. I may write a supplement or two for it if the mood strikes. I really wish more publishers would follow suit on pdfs of their core rules. I think a lot more players would come into the fold.
Here's to your continued success with the Legend line.
Regards. Peter Robbins