I had a similar problem, but with the Netgear MA401 PCMCIA card with the orinico_cs module. However, when I switched to the prism2 drivers from
linux-wlan, the MA401 has worked flawlessly ever since.
Strangely, other members here have posted that they had the exact opposite results with the MA401.
I don't have the Netgear PCI wireless model, so take a grain of salt with my advice. But you might as well try the linux-wlan prism2 modules and see if they are an improvement.