0.4.0 posting bad request data to protobuf service layer

[localshred]

We are using for our protobuf service layer a java server and the ruby app we're running is the client. When doing a request from the ruby client, calling the java RPC service, the java service returns bad request data. We also get a bad stack trace on the ruby side, saying invalid value: nil
Doing some grep-ing it is happening in this file: lib/protobuf/message/field.rb on 691

My ruby env is Ruby 1.9.1p243 (2009-07-16 revision 24175) [x86_64-linux]
We're using rprotoc 0.4.0, which we know is the experimental branch.
Unfortunately rprotoc 0.3.3 doesn't work with ruby 1.9.1 (having TCPSocket readbyte issues - invalid number of params)

Sample Ruby code:
rpc_request = Cerebro::UserAuthorizationParams.new
rpc_request.email = params[:email]
rpc_request.hash = Digest::SHA1.hexdigest(params[:password])
rpc_response = Cerebro::User.new

rpc_client = Protobuf::Rpc::Client.new('localhost', 7575)
rpc_client.call(:authorize , rpc_request , rpc_response) # throws the error of "TypeError - Invalid value: nil"

Java protobuf is reporting:
com.googlecode.protobuf.socketrpc.SocketRpcServer$Handler handleError
WARNING: BAD_REQUEST_DATA: Bad request data from client
com.google.protobuf.InvalidProtocolBufferException: While parsing a protocol message, the input ended unexpectedly in the middle of a field. This could mean either than the input has been truncated or that an embedded message misreported its own length.
at com.google.protobuf.InvalidProtocolBufferException.truncatedMessage(InvalidProtocolBufferException.java:49)
at com.google.protobuf.CodedInputStream.refillBuffer(CodedInputStream.java:691)
at com.google.protobuf.CodedInputStream.readRawBytes(CodedInputStream.java:756)
at com.google.protobuf.CodedInputStream.readBytes(CodedInputStream.java:274)
at com.google.protobuf.UnknownFieldSet$Builder.mergeFieldFrom(UnknownFieldSet.java:484)
at com.google.protobuf.GeneratedMessage$Builder.parseUnknownField(GeneratedMessage.java:271)
at com.googlecode.protobuf.socketrpc.SocketRpcProtos$Request$Builder.mergeFrom(SocketRpcProtos.java:371)
at com.googlecode.protobuf.socketrpc.SocketRpcProtos$Request$Builder.mergeFrom(SocketRpcProtos.java:1)
at com.google.protobuf.AbstractMessage$Builder.mergeFrom(AbstractMessage.java:244)
at com.google.protobuf.AbstractMessage$Builder.mergeFrom(AbstractMessage.java:182)
at com.google.protobuf.AbstractMessageLite$Builder.mergeFrom(AbstractMessageLite.java:202)
at com.google.protobuf.AbstractMessage$Builder.mergeFrom(AbstractMessage.java:683)
at com.googlecode.protobuf.socketrpc.SocketRpcServer$Handler.callMethod(SocketRpcServer.java:160)
at com.googlecode.protobuf.socketrpc.SocketRpcServer$Handler.run(SocketRpcServer.java:128)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:636)