I think leledumbo may have misread your post.
TortoiseSVN checksum errors probably have to do with corrupt downloads of files from the svn repository on checkout/update.
Trying again until it works - or finding out the cause of what causes the problems [1] would be the solution.
Nothing to do with Laz/the compiler as you said.
[1] network problems, faulty NIC, problematic router, whatever. Not my speciality, I'm sorry.