I added shared and particular alias in the use command and eliminated _tally since you can count to a variable.

That's it.

>?
>>>Excellent!
>>>Can you take a look on the following?
>>>

ccount=getfiltercount("mytable", "between(id,521548,529785)")
>>>thisform.txt1.value=ccount
>>>
>>>function getfiltercount(tctable, tcfiltercondition)
>>>	local lnselect, lncount
>>>	lnselect = select() && Save current work alias!
>>>	select 0
>>>	use (tctable) again alias TempCount shared
>>>	count for &tcfiltercondition to lnCount
>>>	use
>>>	select(lnselect)
>>>	return (transform(lncount))
>>>endfunc
>>>

>>>
>>>
>>>
>>
>>See two minor fixes inside.