I would certainly be very careful about using that. Text files in Linux systems use LF line endings, but Windows uses CR/LF so you would need to be sure that you use a text editor which preserves the correct line endings, or you might end up making the file unusable.
The other thing to be aware of is that it only fully supports ext2fs file systems, which are almost unused in modern Linux systems. It partly supports ext3fs (the journalled version of ext2fs) but there seem to be some caveats about this, and I would be very wary about trusting it. Other Linux file systems (and there are many) aren't supported at all.
Sorry if i seem to be pouring cold water, but I really think that if you need to edit files on a Linux system which you can't boot, the best and safest way would be to use one of the many live Linux CDs.