C#: Anything wrong with setting HttpContext.Current in a parallel thread?

I’m using a library that relies on HttpContext.Current. The library is Facebook C# SDK, but my question should apply in other scenarios as well. I’d like to use this library from inside of a parallel thread. However, HttpContext.Current is not available in the parallel thread, so I’m thinking about caching it to a local variable and then setting it in the parallel thread like this:

File Access Strategy in a Multi-Threaded Environment (Web App)

I have a file which is an XML representation of some data that is taken from a Web service and cached locally within a Web Application. The idea being is that this data is very static, but just might change. So I have set it up to cache to a file, and stuck a monitor against it to check if it has been deleted. Once deleted, the file will be refreshed from its source and rebuilt.