Using .NET and HttpResponse I can successfully fetch mutations and copy number alterations successfully for a gene list using the web-API url below; however, when using "mrna" there is a "can't find study error"

url = "http://www.cbioportal.org/webservice.do?cmd=getProfileData&case_set_id=" & cbiolist(d) & "_all&genetic_profile_id=" & cbiolist(d) & "_mrna&gene_list=" & genelist

Any suggestions? I am working only with the "Provisional" TGCA sets, most of which have mRNA expression.