i just bought galaxy ace and upgraded to 2.3.4 DDKQ6 whenever i use wifi at home it runs excellent at these settings.

Encryption Technique > TKIP
Authentication > WPA-PSK
Security Mode> WPA/WPA2-personal ( psk )

but in my office it shows high signals but doesn't run at all, my office router settings are

Encryption Technique > Automatic
Security Mode> OPEN

Note: both routers are same model TP-LINK TL-WR642G 108M

is there something wrong with encryption mode ?