Here's proper declaration. Notice that parameters that have to be passed by referemce should be declared as such. It's also a good idea to keep parameter names in DECLARE. It makes code easier to read.

DECLARE INTEGER GetPrinterDriver IN winspool.drv ;
	INTEGER hPrinter, ;
	STRING pEnvironment, ;
	INTEGER Level, ;
	STRING @pDriverInfo, ;
	INTEGER cbBuf, ;
	INTEGER @pcbNeeded    

>Sorry about that

>DECLARE INTEGER GetPrinterDriver IN winspool.drv ;
>	INTEGER, ;
>	STRING, ;
>	INTEGER, ;
>	STRING, ;
>	INTEGER, ;
>	INTEGER
>