sudo wpa_supplicant -Dwext -iwlan0 -c /etc/wpa_supplicant/my.conf -B
Would be a typo.
Correct
sudo wpa_supplicant -Dwext -iwlan0 -c/etc/wpa_supplicant/my.conf -B
No space between the -c and /etc/wpa_supplicant/my.conf.
That's how wpa_supplicant's man page states to format the options. I've no clue if it actually makes a difference?
As I said the notes I linked were just the the result of of my own debugging and experimentation some years ago when I was also having problems with desktop gui wifi applets
The -Dwext may be incorrect.? (It must have been what I needed). From the man page. Try this (with the other steps)
wpa_supplicant -iwlan0 -c/etc/wpa_supplicant.conf -d
And thiswpa_supplicant -Dnl80211 -iwlan0 -c/etc/wpa_supplicant.conf -d
The -d at the end enables debugging output.I wouldn't be suggesting using wpa_supplicant if things were working already
But imho when things aren't working it is sometimes best to go down to the basic level, with no scripts and gui's and see what is happening.