Try this:
Start TopoFusion
Add one file with a track
Make it active and make a network, go with the default file name and location.
This works
Now remove the just created file/network
Make the original file active
Make a network, again
bingo!
Log is included below, A gpx file(s) with ofending tracks available on request
TopoFusion 2.01 Log Begin
Windows Major Version: 5
Windows Minor Version: 1
Windows Build Number : 2600
Windows Platform ID Â : 2
Windows CSD Version  : Service Pack 1
Initializing DirectDraw
Color Info : BBP = 32
Color Info : Sizes : R=8, G=8, B=8
Color Info : Shifts : R=16, G=8, B=0
DirectDraw : Driver "Dell 8100" (nv4_disp.dll)
DirectDraw : Total Video Memory : 7864320
DirectDraw : Free Video Memory : 7555072
DirectDraw : Hardware supports blits
DirectDraw : Hardware supports asynchronous blits
DirectDraw : Hardware supports colorfill on blits
DirectDraw : Hardware supports stretchblit
DirectDraw : Hardware supports colorkeying
DirectDraw : Hardware supports source colorkey
Creating Surfaces
BackBuffer: Width=186, Height=363, was created in Video Memory
Creating Sprites
Successfully Created Surfaces
Initializing Memory Pool
Total Physical Memory: 267870208
Physical Memory Free: 55439360
Memory Load: 79 percent
Tile Cache Size = 101
30 surfaces created in (local) video memory
71 surfaces created in system memory
Initializing Winsock
Initializing Threads
Initializing Index File
Initialization Complete
Releasing other Surfaces
Creating Surfaces
DirectX Error [3519]: DirectDraw does not have enough memory to perform the operation.
BackBuffer: Width=1594, Height=929, was created in Video Memory
Creating Sprites
Successfully Created Surfaces
recreateVideoMemoryPool: Finishing up
Caught Exception:
Function: ManagerThread (Network)
Exception: Access Violation
Caught Exception:
Function: Paint
Exception: Access Violation
DirectX Error [2277]: Access to this surface is being refused because the surface is already locked by another thread.
