Try the TYPE() command and enclose the field in quotes "". Have you also read the VFP help on these commands?
USE config2
IF TYPE( "config2.version" ) <> "U"
=MESSAGEBOX("field exist")
ELSE
=MESSAGEBOX("field does not exist")
ENDIF
In the End, we will remember not the words of our enemies, but the silence of our friends - Martin Luther King, Jr.