While starting the server, I get this error in CMD: 
"Error while compiling: ActiveSort.cs(416,25): error CS1503: Argument `#1' cannot convert `ItemId' expression to type `uint'"

I also get this error with another plugin: 
"Error while compiling: BotReSpawn.cs(976,34): error CS0029: Cannot implicitly convert type `uint' to `ItemId'"

It feels like its the same problem, for both plugins.
And it should not be plugin related, since other people is compiling them just fine. 

What could it be? Thanks