Where is the return value? (solved but with exit error)

[zarsoft]

#include <basic.bas>

#define _LET 241
#define _VAL 176

LET exp$ = "3/4"
PRINT exp$;"= ?"
LET s$ = CHR$(_LET, CODE "r",CODE "=",_VAL)
LET s$ = s$ + """" + exp$ + """"
EvalBasic(s$)

LET vars = PEEK 23627+256*PEEK 23628 ' 23799
IF vars <> 23799 THEN PRINT "Error: Vars addr at ";vars

DIM w AS FLOAT AT 23799+1
PRINT CHR$(PEEK 23799);"= ";w


Output:
r= 0.75

This works but when program exits I got this error message:
? ?E, 30:1