I have similar problem with my BB9700. I can use wifi in office and free wifi hotspots provided by the carrier without any problem.
I could connect to my wifi at home, however, the connection drops every time just after a successful connection. But, other equipments i.e. desktop, notebook are ok.
It seems that both my home router and BB are working fine with other equipment. But, they are just not compatible with each other. The brand of my router is Buffalo G300N.
I searched all possible websites over the world can try to solve the problem. After about 1 more month searching and test. I finally locate the problem. The problem is at the "router setting".
In Buffalo, the default setting for channel is "auto". This is the root of the problem. When there is interference around, the channel will switch for a better one, then the connection would drop since the reception of BB is not stronger than desktop and notebook. How to solve it? Try to switch the "auto channel" function to "manual". Let say, Channel 1, if it is not perfect, try channel 6 and 11. After that, my problem got fixed. Trial and error are very painful and time consuming. Hope these could help. From BB User in Hong Kong