Are you sure the AP is set to /b speed, or "mixed"?
Here's my "Wifi Checklist" that I've posted a bunch of times on Palm.com'sum:
Wifi Problem Checklist (I'm assuming you know how to access your router's internal settings).
1. Are you using an encryption scheme? WEP? Hex or ASCII? What bit depth, 64 or 128? WPA? Entered the exact key into your Palm? (Remember, 64-bit Hex on the router = 40-bit Hex on Palm, 128 router = 104 on Palm). If using "Passphrase", what is the ACTUAL KEY the passphrase generates? Put that into your Palm!
2. Is your router an 802.11/g model? Is it set it to either "mixed" mode or "/g AND /b"? (The Palm is an 802.11/b model). If the router is set to "/g Only" it won't work.
3. Are you using MAC (Media Access Control) filtering in your router? If so, have you added the Palm's MAC? (On the TX, the MAC address is printed on the back of the unit).
4. Try entering the following address into your Web Browser on your Palm and see if a page opens:
http://66.54.39.105 If it does open, then you need to enter the DNS (found inside your router sometimes labled "Primary DNS and Secondary DNS") numbers manually into your settings for the Wifi Connection you use. (Wifi icon/Prefs/Setup/<highlight your router> /Edit /Configure /Details /Advanced/Change DNS server to manual and enter the numbers.)
5. Have you tried unchecking "Conserve Power" from the Palm's "Wifi/Prefs"? (Palm TX ONLY -This seems to be causing a conflict on some routers).
6. Can you connect to any other router/Wifi Hotspot with your Palm? (If you can, then the configuration between your problem router and the Palm is not correct).