I seem to be having a similar problem. Every time I try to use the ladsat tileset TF crashes on me. Here is the log file that gets generated. I downloaded the 2,18 version when I read this thread, but it didn't seem to help. I've tried different settings on the Preferences->Internet tab, but they all generate the same result. The other tile sets work fine, but the landsat immediately crashes me. I'll try another box to see if it is something in the hardware that is causing a problem.
TopoFusion 2.18 Log Begin
Windows Major Version: 5
Windows Minor Version: 1
Windows Build Number : 2600
Windows Platform ID Â : 2
Windows CSD Version  : Service Pack 2
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 "ALL-IN-WONDER 9700 SERIES " (ati2dvag.dll)
DirectDraw : Total Video Memory : 126791680
DirectDraw : Free Video Memory : 126791680
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=236, Height=494, was created in Video Memory
TileBuffer: Width=636, Height=894, was created in Video Memory
Creating Sprites
Successfully Created Surfaces
Initializing Memory Pool
Total Physical Memory: 1073197056
Physical Memory Free: 477769728
Memory Load: 55 percent
Tile Cache Size = 1253
626 surfaces created in (local) video memory
627 surfaces created in system memory
Initializing Winsock
Initializing Threads
Initializing Index File
Sorting Index File. Â Number of entries: 1354294
Time to sort index file: 23.11 seconds
Initialization Complete
Releasing other Surfaces
Creating Surfaces
BackBuffer: Width=1274, Height=744, was created in Video Memory
TileBuffer: Width=1674, Height=1144, was created in Video Memory
Creating Sprites
Successfully Created Surfaces
recreateVideoMemoryPool: Finishing up
handling chunked data, bufsize = 10242
found chunked in datahandling chunked data, bufsize = 10182
handling chunked data, bufsize = 10114