Command bedtools makewindows -w 200 -s 50 -g resources/hg19.autoX.chrom.sizes not working

[gurudatta-patil]

hg19.autoX.chrom.sizes

chr1    249250621
chr10   135534747
chr11   135006516
chr12   133851895
chr13   115169878
chr14   107349540
chr15   102531392
chr16   90354753
chr17   81195210
chr18   78077248
chr19   59128983
chr2    243199373
chr20   63025520
chr21   48129895
chr22   51304566
chr3    198022430
chr4    191154276
chr5    180915260
chr6    171115067
chr7    159138663
chr8    146364022
chr9    141213431
chrX    155270560

this command

bedtools makewindows -w 200 -s 50 -g resources/hg19.autoX.chrom.sizes

giving error as:

Error: The genome file resources/hg19.autoX.chrom.sizes has no valid entries (are you sure it's a 2-column bedtools genome file). Exiting.