First of all, which I assume you know, is that the computer must always be on from which the server is being hosted. Secondly what kind of computer is this? If it has a GUI (like windows or mac and some distributions of linux/ubuntu/debian) it will make things much easier for changing things to the correct setting. Third, I would like to know what the desired outcome is, and what mods you have installed, forge version, debug.log, ETC, the basics.
For Biomes O' Plenty, you have to make sure that the world type is set to a Biomes O' Plenty world type. So you'll have to reset your world.
And finally, I assume you know that most mods MUST be on both the client and server for it to function properly. So for example, if you want lucky blocks, that must be in the server mods folder, AND in your .minecraft mod folder.
For me to fully finish helping you I need the rest of the information that I stated above.
Cheers,
Foonicular