"Column number is less than one." for sparse matrix format

I have a sparsematrix.mat of size 5036 * 12570
The sparsematrix looks like this:
5036 12570 34996
7582 1
11829 2
997 1 9301 1
1377 2 7582 19
241 1 1282 3 3001 1 3062 1 3757 1 4278 1 4423 2 4964 1 5967 1 6064 1 8407 1 9927 1 9978 2 10452 1 11010 1 11692 1
1100 1 1973 1 3331 1 4635 1 5891 1 7910 1 7993 1 12149 1 12371 2
7967 2 9935 2 11632 4 11804 2 12305 4
8870 2 11829 2

I'm pretty sure that the index starts from 1 instead of 0 and there should be no 0 in this file. But I still got the
following error:

./vcluster sparsematrix.mat 10
Error: Column number is less than one. Ncols=12570, ColNum=0, Row=1

When I transform the matrix into dense format, it works ok. Just don't understand why this is happening.