Imagenet_Tech and DavidZuts are quite correct in stating that you will only get PCL XL errors with a PCL6 print stream.
If such errors are repeatable (i.e. exactly the same when reprinting the same document, using the same driver, to the same device), then it is likely that they are caused by a driver (or driver settings) fault.
If the errors are random, they are much more likely to be the result of intermittent corruptions of the generated print stream between the workstation and the device (check cables, ports, switches, etc.).
PCL6 has a reputation for being a bit glitchy because of these errors; they are reported because the language is highly structured, and any departure from this structure is relatively easy for the language interpreter in the printer to detect.
However, you may still get errors reported with PCL5 (e.g. 'page too complex') or PostScript (e.g. 'stack error'), or (especially with PCL5) you may get no reported errors, but the print output may not be as expected (some time ago, there was a problem whereby underscores were routinely missing), since the PCL5 interpreter will just soldier on the best it can (ignoring any corrupt escape sequences).