cannot open *.kmerFreq file after pregraph, then exit

My command:

SOAPdenovo-63mer all -s config_file -K 31 -R -o soapdenovo_asm 1>ass.log 2>ass.err

config_file:

max_rd_len=100
[LIB]
avg_ins=200reverse_seq=0
asm_flags=3
rd_len_cutoff=100
rank=1
pair_num_cutoff=3
map_len=32
q1=/mnt/hgfs/ubt22share/2.HQdata1/data/CDC012_R1.fq.gz
q2=/mnt/hgfs/ubt22share/2.HQdata1/data/CDC012_R2.fq.gz
