Is the "tabix" an application that runs under its own user account (that may not have correct permissions)? Reason I ask is it looks like something has been shelled out:

sh: 1: /home/[user]/tabix-0.2.6
[download]

To see if *you* have correct permissions:

perl -E 'open my $fh, ">", "/home/[user]/tabix-0.2.6/test.txt" or die 
+$!'
[download]

If you don't get a permission denied error, the problem is elsewhere. Perhaps also show the perms you do have on the dir.

The chunk of Perl code that wraps this work may be helpful to us to troubleshoot to help as well.