When trying to install the ZipMaster package on Delphi 4, I encountered the following problems when installing the package: [Error] ZipMstr.pas(3073): Not enough actual parameters fault application.MessageBox(pchar(IntToStr(r)), 'Abort'); fix? application.MessageBox(pchar(IntToStr(r)), 'Abort',MB_OK); If I add the in my case mandatory parameter, this fault is gone. Is it correct? [Error] ZipMstr.pas(5008): Undeclared identifier: 'IMAGE_DOS_HEADER' fault DOSHead: ^IMAGE_DOS_HEADER; [Error] ZipMstr.pas(5026): 'THEN' expected but identifier 'e_magic' found fault if DOSHead.e_magic <> IMAGE_DOS_SIGNATURE then These two faults are related. It seems that in the file ZipStructs.pas the definition of the type is within an {$IFDEF VERD2D3} block. Since D4 is outside, it skips this part, so in the ZipMstr.pas the faults occur. Commenting out this $IFDEF and its ENDIF will allow compilation to complete. As I am not (yet) up to date with the package, please let me know if this is the way to fix it or is there more to it? I downloaded from Russel's page. PB