GT-I5500 Wi-Fi error
I performed two steps to fix the issue:


Settings -> Wireless &amp; network settings -> Wi-Fi settings -> click menu button and select Advanced, Select Wi-Fi sleep policy - > Select Never.
Dial *#*#526#*#* for WLAN Diagnostics. This will reload the Wi-Fi driver (I tried this before without step 1 and it rebooted my mobile).