Make sure you have a symsrv.dll and symsrv.yes in the directory where symsrv_convert is looking. For me this was C:/Windows/SysWOW64/
./symsrv_convert.exe http://msdl.microsoft.com/download/symbols /c/symcachet d3d10_1.pdb 64BCE4F6B72340F19C453569A3F4A13B1
To build symsrv_convert you'll need to use google-breakpad/src/tools/windows/converter