This is the same error as this thread: http://www.diydatarecovery.nl/forum/index.php/topic,310.0.html
The error occurs during "Analyze", and reads "Run-time error '28': Out of stack space".
but I couldn't find a way to add to that thread, perhaps because it is old.
Windows 7 64-bit, Disktune v1.1.31, running in VSS-safe mode.
The drive has 170,108 files in 43,481 folders.
Let me know if I can provide any other useful info!