Unknown index type error of SelectVariants

Good day to you! I ran a selectvariant command by
nohup java -Xmx5g -jar /home/wuwei/software/GenomeAnalysisTK-3.8-0-ge9d806836/GenomeAnalysisTK.jar -R $referrence -T SelectVariants --variant:VCF file1.vcf --concordance:VCF file2.vcf -o dw.concordance.vcf &
However, I got a error message like this:"Unknown index type. magic number: 0x69662323; type 1868981612". I am quite sure the referrence fasta has no problem. I regenerate the file1.vcf and file2.vcf and rerunned selectvariants, but unfortunately, I am still receiving the same error message. I am really confused.
I am waiting for you answer.