Error rebuilding reporting database Sitecore 7.5

Question

I'm trying to rebuild the reporting database, And after applying the required configuration and when opening sitecore/admin/RebuildReportingDB.aspx and clicking on start button the following error appears in the log files:

    4100 2016:08:11 06:58:20 ERROR Exception when executing agent processing/taskAgent
Exception: System.IO.FileFormatException
Message: Element 'WorkItemType' does not match any field or property of class Sitecore.Analytics.Processing.ProcessingTask.
Source: MongoDB.Bson
   at MongoDB.Bson.Serialization.BsonClassMapSerializer.Deserialize(BsonReader bsonReader, Type nominalType, Type actualType, IBsonSerializationOptions options)
   at MongoDB.Bson.Serialization.BsonClassMapSerializer.Deserialize(BsonReader bsonReader, Type nominalType, IBsonSerializationOptions options)
   at MongoDB.Driver.Internal.MongoReplyMessage`1.ReadFrom(BsonBuffer buffer, IBsonSerializationOptions serializationOptions)
   at MongoDB.Driver.Internal.MongoConnection.ReceiveMessage[TDocument](BsonBinaryReaderSettings readerSettings, IBsonSerializer serializer, IBsonSerializationOptions serializationOptions)
   at MongoDB.Driver.Operations.QueryOperation`1.GetFirstBatch(IConnectionProvider connectionProvider)
   at MongoDB.Driver.Operations.QueryOperation`1.<Execute>d__0.MoveNext()
   at System.Linq.Enumerable.FirstOrDefault[TSource](IEnumerable`1 source)
   at Sitecore.Analytics.Processing.TaskQueue.TryGetNext(Guid taskIdBoundary, ProcessingTask& workItem)
   at Sitecore.Analytics.Processing.TasksAgent.Execute()
   at Sitecore.Analytics.Core.BackgroundService.Run()

Any ideas?