I had the same problem on my 2001 330i.....both drivers and passenger side windows. I found the web site below which explains how to repair the regulator with ty-wraps and I just "fixed" both windows today. I'm not sure how long it will last, but it was worth trying. The window regulators are pretty pricey.
Whether you try the ty-wrap repair or just replace the regulators, it's a relatively easy job if you have some mechanical ability.
On thing to note: Disconnect the battery before unpluging the side airbag. Do not reconnect the battery with the airbag module unplugged or the airbag light won't go out and you'll need a scan tool or dealer to reset it. That was the one mistake I made. That means you'll need to get the window in the proper position to remove the 2 bolts that hold the glass to the regulator before disconnecting the battery and the airbag. E46 Window Regulator
If anyone in Southern CT has or knows of someone with an SRS scan/reset tool with a 16 pin connector that they would let me use to reset the airbag light, it would be greatly appreciated.