As DepotINTL indicates, if you use a PCL5 (or PostScript) driver, then you won't get PCL XL errors, since PCL XL is the underlying name of the Page Description Language associated with PCL6.
HP appears to offer drivers, for the LaserJet 4100 and LaserJet 4050, for all three PDLs, for Windows Server 2008 R2, although they are are all Universal Printer Driver versions.
But in switching to a different PDL you may, of course, avoid one error only (perhaps) to find different problems with your output.