Rather than always reading in a set number of bytes, it's better to read up until the first "newline" character (0x0A), using something like C's fgets() function with some reasonable maximum line length >=50, if your software supports that. This way any line noise, etc. causing a corrupt or incomplete read will only clobber a line or two, rather than getting you out of alignment and propagating through to all subsequent reads.
Also, be sure to use that provided checksum byte at the end (described in the Mate Serial Comm. Guide) to verify each line before accepting it as valid data. It would be good to have some provision in your code for dealing with missing/invalid samples in a reasonable way, perhaps interpolating from the nearest valid lines on either side of the dropout.
Not that you should be getting dropouts & corruption in the first place (the one time I had such trouble it was due to a flaky USB-Serial dongle, like Julie mentioned), but it's good to be prepared for them just in case.