[Beginner] ntfs-3g causes sparse error, own compilation won't get executed.

Dachschaden

First post and before I get started: I am a somewhat experienced linux user and a somewhat decent C programmer, but I've never been before in kernel development, so please be nice. Also sorry for bad english, as I am a german native speaker, and I was never good in school english.

My story: I was running a perl script that would rename and symlink certain files (or better lots of them, about 300.000 and more ) on a ntfs partition when I suddenly got an I/O error. Since I can reproduce the error with a simple cp I will print cp's output instead of my script's (besides they are the same):

cp: cannot create regular file `abc': Input/output error

The error code is "Input/output error", errno is -1.

Looking into /var/log/syslog, I found this:

xxx zzz ntfs-3g[13251]: ntfs_rl_sparse: bad runlist: Invalid argument
xxx zzz ntfs-3g[13251]: Could not check whether sparse
xxx zzz ntfs-3g[13251]: Mapping pairs update failed: Input/output error
xxx zzz ntfs-3g[13251]: ntfs_rl_sparse: bad runlist: Invalid argument
xxx zzz ntfs-3g[13251]: Could not check whether sparse
xxx zzz ntfs-3g[13251]: Failed to restore old mapping pairs: Input/output error
xxx zzz ntfs-3g[13251]: Failed to enlarge attribute: Input/output error
xxx zzz ntfs-3g[13251]: ntfs_attr_mst_pwrite: written=-1: Input/output error
xxx zzz ntfs-3g[13251]: Failed to write index block 40859, inode 593287: Input/output error
xxx zzz ntfs-3g[13251]: Failed to add entry to the index: Input/output error

According to what I know (and please correct me if I am wrong), ntfs gets mounted by the kernel module "fuse", which enables user applications like "mount" to load in drivers from user space that would support certain file systems.

Well, before writing an email to the authors I'd like to try debugging the code myself, so I fetched the ntfs-3g source from my distros reposiories, found the two called for "ntfs_rl_sparse" (all in libntfs-3g/attrib.c), made one or two custom error messages next to the actual error messages (to confirm that it gets actually executed - as said I am a newbie in kernel module development), ./configured, maked and make installed the driver and re-mounted my ntfs partition. But alas, even though the error continues, my "special printouts" (done with ntfs_log_errors) aren't shown.

I know that the proc does not get a valid runlist (which, if I am guessing right, means that there're some problems with rebulding sparsed file, right?), but how can I be sure if I can't debug the code?

What do I need to do to insert my custom ntfs driver into fuse? I thought it's loaded in dynamically.

Using Debian on a 3.7 kernel.

Oh btw: this is df -h | grep 'sda2':

/dev/sda2 586G 576G 11G 99% /mnt/Win

And df -i | grep 'sda2':

/dev/sda2 12868436 1900303 10968133 15% /mnt/Win

I know there are just 11 GB free on /dev/sda2, but the script could finish like 300.000 symlinks before breaking inoperatable - and it freed 2 GB already in the process, so I don't think the spare memory is the cause.