MySQL on Buffalo TS-X Series (no replies)

Hi Pros,

I need to have MySQL's data being backup everyday, so I bought Buffalo TS-X Series NAS for this purpose.

I mapped NAS above as [Z:] network driver on my 2008 server, modify my.ini for "datadir" points to "Z:\data\" folder, start MySQL by command line using mysqld-nt.exe...
MySQL starts normally and MySQL Query Browser works out of box.

However, mysqld-nt.exe crashes monthly at the 1st.

Are there anyone facing this problem? And has solved it?
Is there any special task in MySQL that is done at the end or beginning of every month?

(Sorry for my English)