As a module is a viapro one, I'm assuming that the north and southbridge are both from Via. I seem to remember that Via chipsets can be a bit problematic with lm_sensors - which isn't much help to you, I know. When the temp hardware isn't up to scratch either, then it's just a grind getting it to work properly.
(It was for this reason that I went for Intel chipset on my latest board. Not the best, but it works when you want to make sure your cpu isn't frying).
The good news is that lm_sensors v2.6.4 looks like it is going to be released this month and according to the website, looks like it supports far more chipsets, including Via .... hope it does the trick.
BTW - no workarounds on the site or on the net?