The "Cannot map ... to SOAP/OM" error

Though the issue has been reported by several people in different cases,
didnt find a satisfactory solution. Is this a bug that soap4r is going
to resolve say in 1.5.9?

I created client side objects via the ‘wsdl2ruby’ utility. Was able to
call upon an API which did not take any parameters but as soon as try to
send a parameter this issue surfaces. Any decent pointers for this?

vendor/gems/soap4r-1.5.8/lib/soap/mapping/encodedregistry.rb:356:in
_obj2soap' vendor/gems/soap4r-1.5.8/lib/soap/mapping/encodedregistry.rb:301:inobj2soap’
vendor/gems/soap4r-1.5.8/lib/soap/mapping/mapping.rb:131:in _obj2soap' vendor/gems/soap4r-1.5.8/lib/soap/mapping/mapping.rb:54:inobjs2soap’
vendor/gems/soap4r-1.5.8/lib/soap/mapping/mapping.rb:52:in upto' vendor/gems/soap4r-1.5.8/lib/soap/mapping/mapping.rb:52:inobjs2soap’
vendor/gems/soap4r-1.5.8/lib/soap/mapping/mapping.rb:592:in
protect_mapping' vendor/gems/soap4r-1.5.8/lib/soap/mapping/mapping.rb:565:inprotect_threadvars’
vendor/gems/soap4r-1.5.8/lib/soap/mapping/mapping.rb:581:in
protect_mapping' vendor/gems/soap4r-1.5.8/lib/soap/mapping/mapping.rb:51:inobjs2soap’
vendor/gems/soap4r-1.5.8/lib/soap/rpc/proxy.rb:477:in request_rpc_enc' vendor/gems/soap4r-1.5.8/lib/soap/rpc/proxy.rb:459:inrequest_rpc’
vendor/gems/soap4r-1.5.8/lib/soap/rpc/proxy.rb:414:in request_body' vendor/gems/soap4r-1.5.8/lib/soap/rpc/proxy.rb:127:incall’
vendor/gems/soap4r-1.5.8/lib/soap/rpc/driver.rb:181:in `call’