Help with Siemens Macro no data when reading in file.

I have a macro that has me stumped. On a Siemens 810D, I can write to a fi
le but I cannot read the data back in. I don't get an error from the read c
ommand. Error Boolean = 0 , I just get no data. VALSTR[1] = VALSTR[2]
= blank (no data).
Here is a program snippet:
N7 DEF INT FILE_ERROR ; READ WRITE ERROR RETURN
N8 DEF STRING[255] VALSTR[2] ;NUMBER AS A STRING
N10 DEF REAL SLNUM ; NUMBER
N12 DEF BOOL VALIS ;TEST RETURN OF ISNUMBER
N14
N20 READ(FILE_ERROR, "/_N_SPF_DIR/_N_TESTFILE_SPF", 0, 1, VALSTR)
N22 IF FILE_ERROR 0
N24 MSG(