server mod removing Issue

[UltraTechX]

so, i recently remove Biomes O Plenty mod on my server, but after that it just spams the console with things like :

[server Thread/Error] [FML]: Unidentified Item: BiomesOPlenty:redwood stairs

 

after that it wont continue starting up, how can I make these errors go away so it will start up

[shadowfacts]

At the end of the log there should be a message saying that you need to run a special command to confirm the removal of the Biomes O Plenty block. Additionally, because you're removing a world gen mod, your world will probably be corrupted unless you hadn't set the generator in the server properties.

 

Side note: This topic should be in the Support & Bug Reports forum, as this is not about a mod you made.