In MapXtreme, Bing Map is supported through TAB file.
To open this you need to set Bing license key through any one of following approaches:
1. Use the Registry key variable "SOFTWARE\MapInfo\MapXtreme\9.0.0\TileServerKey". Where 9.0.0 is MapXtreme version.
2. Use the system environment variable MI_TILE_SERVER_KEY.
If you are running 32 bit then set key of 32 bit key of bing
If you are running 64 bit then set key of 64 bit key of bing