Exception occurred: Sharing violation on path /home/sleon/glproto/glproto.csproj

System.IO.IOException: Sharing violation on path /home/sleon/glproto/glproto.csproj
  at System.IO.FileStream..ctor (System.String name, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, Boolean anonymous, FileOptions options) [0x00000] 
  at System.IO.FileStream..ctor (System.String name, FileMode mode) [0x00000] 
  at (wrapper remoting-invoke-with-check) System.IO.FileStream:.ctor (string,System.IO.FileMode)
  at MonoDevelop.Prj2Make.SlnMaker.CreatePrjxFromCsproj (System.String csprojFileName, IProgressMonitor monitor) [0x00000]