Answered Error: checksum mismatch, and Error : line number is not last line number+1

Those are really not errors per se, but warnings.

The error it is complainging about is buried somewhere up above in that list, scroll back and look for the word "ERROR"

However, 9 times out of 10 the "error" is:

ERROR temperature fell too much during print

There are a number of posts that go into great detail on this error start with the FAQ thread

http://community.robo3d.com/index.php?threads/faq-r1-r1-series-printers.19735/#post-119221