PHP Printing problems

We are running a new app in PHP/Gtk, PHP 4.2.3 on a variety of Windows - 98 and up. We made the decision early on to use the PHP printing functions and avoid the whole .pdf route or having to open a browser window when we don't need it otherwise. Right now, we can generate reports just fine, but we're losing data on a random basis. Ex: Line 4 and 5 print fine, line 6 is missing column 6. Rearrange the sort order and the data for line 6 appears, something else drops off. We thought it was a memory issue, but we switched it to our main LJ with 256 RAM with the same results. Also tried switching from a PCL 6 driver to a PS one; no luck. Any thoughts? thanks Madeleine d.