Try deleting /data/misc/wpa_supplicant.conf then reboot.
This will wipe all of your saved connections, but generally fixes wifi issues.
When I flashed this, all I had to do was reboot a couple of times, and wifi kept working.
Which version did you flash? If 1.5, did you also flash the status bar patch9-hich also fixes a couple of other issues?
If so, it sounds like a bad download. I get root access just fine, I have my statusbar, I get the lockscreen(however sometimes it takes a minute to kick in, dunno about this one, doesn't bother me much), and my power widget loads and works fine(although, don't need it, the toggles are in the statusbar)
I highly recommend downloading 1.5 and the statusbar patch, and flashing both, then booting.
~ E.R.A.