Apparently the answer is no: there is no way to obtain more information from srcsrv.dll.
The Microsoft forums moderators have told me that the message "Données non valides", "Invalid data" is possibly related to the length of the path of the file to be downloaded. This path is combined to the temporary symbol path you've specified in the Visual Studio/WinDBG settings.
e.g. If you've specified
%APPDATA%\Symbols
as local symbol storage, and you're downloading a source file hosted by an HTTP server at the address
http://nightlybuilds.int/sources/get.svc/path/file.cs
the path
%APPDATA%\Symbols\sources\get.svc\path\file.cs
shall not be longer than 255 characters.
Other factors that can affect the behavior of SRCSRV:
- The presence of characters invalid in a classic dos PATH (i.e. other than [0-9 A-Za-z\.])
- The client debugger settings. (e.g. In the Native mode, the symbols for Managed code won't be downloaded. The Modules window will give you some hint about the symbols currently loaded.)