I have been using Ubuntu at work since day one, just over a year. I have never had any problems accessing windows shares on the network before I did a clean install of Ubuntu 11.10 on the laptop they gave me. I had upgraded the desktop at work from 10.04 to 11.10 and I was still able to access the network shares. However, the fresh install of 11.10 did not let me. It kept saying password required for machineX.
- edit /etc/hostname and type the new name that you want.
- edit /etc/hosts and update the corresponding entry in there to match the name you put in the hostname file.
I almost forgot, one other developer at work had the same issue after she installed Ubuntu on her laptop, Changing the hostname worked for her as well.