uri has type STRING rather than OBJECT in Scala and MongoDB integration?

Question

I am working with Play framework(2.2.x) using Scala and MongoDB(v 2.6.11). I am trying to run sample application using in my system, as it is not executing the application and giving the compilation error in application.conf: uri has type STRING rather than OBJECT

application.conf:

mongodb.uri = "mongodb://localhost:27017/mydatabase"

Build.scala:

"org.reactivemongo" %% "reactivemongo" % "0.10.0",
    "org.reactivemongo" %% "play2-reactivemongo" % "0.10.2",
    "com.novus" %% "salat" % "1.9.8",
    "org.mongodb" %% "casbah-gridfs" % "2.7.2",
    "se.radley" %% "play-plugins-salat" % "1.5.0"

Please let me know what is the mistake here and thanks for help in advance !