Package Builder having issues with configurations

Ok my project was perfectly working fine, but after adding reference on visual studio of a web dl and then re-adding the project on to package builder, i keep getting this

Package 'HelpExtension' has unresolved assembly references:
  'Spotfire.Dxp.Worker.ServiceContracts, version 18.10.8513.5432' is referenced by 'Spotfire.Dxp.Web.dll'.
  'TIBCO.EMS, version 1.0.700.12' is referenced by 'Spotfire.Dxp.Web.dll'.

I cant find anything on google and really need help on this! 

(2) Answers