>

>sele csrtable
>go top
>do while .not. eof()
>	rch = csrkey
>	sele employee
>	go top
>	locate for rch=ckey
>	if found()
>		lc = locfle
>		sele csrtable
>		replace locfle with lc
>	enddo
>	skip
>enddo
>

For a start, you could use a SCAN, which saves several commands:

sele csrtable
scan
	rch = csrkey
	sele employee
	go top
	locate for rch=ckey
	if found()
		lc = locfle
		sele csrtable
		replace locfle with lc
	enddo
enddo

Next, you should use full commands (select instead of sele), and give your variables meaningful commands. Also, use variable naming conventions, and make sure your variables are declared. I'll omit renaming the variables for now.

You can omit "go top", since "locate" will start at the top.

In the locate command, I think, it is better to invert (if I understand correctly, ckey is the field, rch the variable), so that Rushmore Optimization works better.

select csrtable
scan
	rch = csrkey
	select employee
	locate for ckey = rch
	if found()
		lc = locfle
		select csrtable
		replace locfle with lc
	enddo
enddo

In your original code, you forgot to unconditionally go back to alias csrtable. (With SCAN, this is implicit.)