Can you send us a log file? Or post any seemingly-relevant errors you see at the end of of armorylog.txt or armorycpplog.txt? It's especially interesting to us if the DB build & scan used to work but doesn't with the new version (because we added stuff that was intended to catch and handle errors in blk*.dat files... maybe that code is misbehaving?)
This is at the end of armorycpplog.txt:
Log file opened at 1393379181: C:\Users\username\AppData\Roaming\Armory\armorycpplog.txt
-INFO - 1393379211: (..\BlockUtils.cpp:1579) Set home directory:
-INFO - 1393379211: (..\BlockUtils.cpp:1601) Set blkfile dir: C:\Users\username\AppData\Roaming\Bitcoin\blocks
-INFO - 1393379211: (..\BlockUtils.cpp:1611) Set leveldb dir: C:\Users\username\AppData\Roaming\Armory\databases
-INFO - 1393379211: (..\BlockUtils.cpp:1567) SetBtcNetworkParams
-INFO - 1393379211: (..\BlockUtils.cpp:3628) Executing: doInitialSyncOnLoad_Rebuild
-INFO - 1393379211: (..\BlockUtils.cpp:3653) Number of registered addr: 485
-INFO - 1393379211: (..\leveldb_wrapper.cpp:399) Opening databases...
-WARN - 1393379211: (..\leveldb_wrapper.cpp:303) ***LevelDB Error: IO error: C:\Users\username\AppData\Roaming\Armory\databases/leveldb_headers: Bad file descriptor
-ERROR - 1393379211: (..\leveldb_wrapper.cpp:453) Failed to open database! DB: 0
Armorylog.txt doesn't have anything that looks unusual, but I can send it to you if you need more info.