RB450G+microSD=errors - help

Hi!
I install Kingston microSD HC 4gb C04G Japan class 4 memory card
in Stores - formated it, add new store for webcache.
After several hours of work all be ok, cache was on memory card, and watchdog reboots the device.
I format and chek SD card - its ok
Here is log screenshot.

Please help to sovle this problem.
err_scr1.jpg

That errors come again with Transcend microSD 2gb
How to fix that?

http://sysunconfig.net/unixtips/stale_nfs.txt