Try with parameters, without converting to string:

dDate = inven.refdate
csqldelete = [DELETE FROM itemldgr Where docdate <= ?dDate]
If SQLEXEC(nConn,csqldelete) <= 0
   Aerror(car)
   MessageBox(Aerror(car(2)))
Endif

>I'm using VFP8 with SQLSERVER2000 as DB backend. It's my first time encountering this strange error:
>

>cDate = Dtoc(inven.refdate)
>csqldelete = [DELETE FROM itemldgr Where docdate <= ']+cdate+[']
>If SQLEXEC(nConn,csqldelete) <= 0
>   Aerror(car)
>   MessageBox(Aerror(car(2)))
>Endif
>

>Above gives me:
>Connectivity Error: [Microsoft][ODBC SQL Server Driver][SQL Server]Syntax error converting character string to smalldatetime data type.
>
>What's missing???