This is either because you need to change to using OutputTo method (see earlier tip) or you need to set scaling on (Auto Resize) in your report, in design mode.
When using DynaPDF.DLL with Access 2007, 2010 and 2013 to print a report, you may only get half a page. To solve, you have to dispense with ConvertReportToPDF function and use Docmd.OutputTo instead:-
numVersioneAccess = CLng(SysCmd(acSysCmdAccessVer))
If numVersioneAccess <= 10 Then ‘ Access 2003
blRet = ConvertReportToPDF(vReport1, vbNullString, FilePath, False, False, 150, “”, “”, 0, 0, 0)
Else ‘ Access 2007 or over
DoCmd.OutputTo acOutputReport, vReport1, acFormatPDF, FilePath