I've pasted the exact code in the help for sys(1500) and it doesn't work for me - there's no text pasted in. Doesn't work in VFP7 or VFP9 in developer version of VFP or as an EXE.

From VFP9 Help (and is the same in VFP7):

_CLIPTEXT = "MESSAGEBOX('TEST')" && Command to paste
MODIFY COMMAND myprog NOWAIT && Open a program file
SYS(1500, '_MED_PASTE', '_MEDIT') && Paste menu item