The white screen thing is due to VBA not being able to detect save-types for all games correctly without additional files. Pokemon games require the Flash 128K save type, or you will get a white screen. You can either use vba-over.ini to set everything automatically, or do it manually. You will also get a white screen if you did not delete the incorrect 64K save after setting VBA to Flash 128K or using vba-over.ini.
Simple steps:
Method 1 - If you care about playing all games. (Recommended)
1. You need to use the vba-over.ini, which is attached here:
http://forums.ngemu.com/visualboy-advance-discussion/63369-how-fix-boktai-pkmn-dbz-smb3.html
2. Unzip the ini file and place it alongside the emulator.
3. Using the emulator, set the save-type to Automatic and Flash 64K
Options > Emulator > Save type
4. Delete the .sav file for the game you want to run, so you are starting a fresh game.
VBA can now detect the correct save type for all games inc. the problematic ones.
Method 2 - If you only care about running Pokemon and no other games.
1. Using the emulator, set the save-type to Automatic and Flash 128K
Options > Emulator > Save type
2. Delete the .sav file for the game you want to run, so you are starting a fresh game.
VBA can now run Pokemon games correctly, although other games that use a different save-type might get broken.