Closed:specifying chromosome sizes and output with bedGraphToBigWig

Question

[chrisclarkson100]

I have a bedgraph of a full genome mm9:

chr1    3049360 3053345 0
chr1    3049360 3053345 0
chr1    3049360 3053345 0
chr1    3049360 3053345 0
chr1    3049360 3053345 0

I want to convert it to a bigwig:

bedGraphToBigWig HET.bedgraph mm9_genome HET.bw

Where the mm9_genome specifies the chromosome sizes.

However I keep getting this error

invalid unsigned integer: "size"

mm9_genome file is as follows:

chr1    197195432
chr2    181748087
chr3    159599783
chr4    155630120
chr5    152537259
chr6    149517037
chr7    152524553
chr8    131738871
chr9    124076172
etc.

Can anyone help?