Can confirm that Feisty always crashes when starting Scan.
Am using the restricted module Atheros Hardware Access Layer (HAL).
Worked fine in Edgy with self compiled MADWIFI Drivers.

ProblemType: Bug
Architecture: i386
Date: 02042007
DistroRelease: Ubuntu 7.04

Here's the bug report:
(no debugging symbols found)
Using host libthread_db library "/lib/tls/i686/cmov/libthread_db.so.1".
..
(no debugging symbols found)
..
[Thread debugging using libthread_db enabled]
[New Thread -1233037616 (LWP 6439)]
[New Thread -1238135920 (LWP 6454)]
...
(no debugging symbols found)
...
0xb73a5237 in QGListIteratorList::add () from /usr/lib/libqt-mt.so.3
#0  0xb73a5237 in QGListIteratorList::add () from /usr/lib/libqt-mt.so.3
#1  0xb73a3e9b in QGListIterator::QGListIterator () from /usr/lib/libqt-mt.so.3
#2  0xb70470b2 in QPtrListIterator<QPostEvent>::QPtrListIterator ()
   from /usr/lib/libqt-mt.so.3
#3  0xb70470dc in QPostEventListIt::QPostEventListIt ()
   from /usr/lib/libqt-mt.so.3
#4  0xb703f88c in QApplication::sendPostedEvents () from /usr/lib/libqt-mt.so.3
#5  0xb703fb28 in QApplication::sendPostedEvents () from /usr/lib/libqt-mt.so.3
#6  0xb6fe50dd in QEventLoop::processEvents () from /usr/lib/libqt-mt.so.3
#7  0xb70590be in QEventLoop::enterLoop () from /usr/lib/libqt-mt.so.3
#8  0xb7058ece in QEventLoop::exec () from /usr/lib/libqt-mt.so.3
#9  0xb7040591 in QApplication::exec () from /usr/lib/libqt-mt.so.3
#10 0x0805b502 in ?? ()
#11 0x080c07a8 in ?? ()
#12 0x080feca8 in ?? ()
#13 0x00000001 in ?? ()
#14 0x00000000 in ?? ()


Some more Info from the Terminal:
 sudo swscanner 
X Error: BadDevice, invalid or uninitialized input device 170
  Major opcode:  148
  Minor opcode:  3
  Resource id:  0x0
Failed to open device
X Error: BadDevice, invalid or uninitialized input device 170
  Major opcode:  148
  Minor opcode:  3
  Resource id:  0x0
Failed to open device
X Error: BadDevice, invalid or uninitialized input device 170
  Major opcode:  148
  Minor opcode:  3
  Resource id:  0x0
Failed to open device
X Error: BadDevice, invalid or uninitialized input device 170
  Major opcode:  148
  Minor opcode:  3
  Resource id:  0x0
Failed to open device
Session management error: Authentication Rejected, reason : None of the authentication protocols specified are supported and host-based authentication failed
kbuildsycoca running...
Running SWScanner version: 0.2.2
Creating aplist...
Creating SWSconfig...
Creating MainWindow...
Creating gpserial...
Creating SWSystemTray...
if(lo)->127.0.0.1/255.0.0.0/0.0.0.0#### level: -65  noise: -208 (140)
Creating scanning thread...

Creating frmconfig...
Tables found:     networks
Tables found:     networks
Deleting frmconfig...
Deleting SWSconfig...
if(lo)->127.0.0.1/255.0.0.0/0.0.0.0#### level: -74  noise: -256 (232)
if(lo)->127.0.0.1/255.0.0.0/0.0.0.0#### level: -248  noise: -172 (30)
if(lo)->127.0.0.1/255.0.0.0/0.0.0.0#### level: -248  noise: -96 (30)
Warning: Driver for device ath0 has been compiled with version 21
of Wireless Extension, while this program supports up to version 17.
Some things may be broken...

if(ath0)->192.168.1.3/255.255.255.0/192.168.1.255####   level: -64  noise: -90 (26)
if(ath0)->192.168.1.3/255.255.255.0/192.168.1.255####   level: -65  noise: -90 (25)
Starting a new scan thread!!
ath0      Scan completed :
New AP found(01): 00:XX:XX:XX:XX:F7
KCrash: Application 'swscanner' crashing...
QSocketNotifier: invalid socket 9 and type 'Read', disabling...
QSocketNotifier: invalid socket 4 and type 'Read', disabling...
QSocketNotifier: invalid socket 7 and type 'Read', disabling...
X Error: BadWindow (invalid Window parameter) 3
  Major opcode:  7
  Minor opcode:  0
  Resource id:  0x18000fc
if(ath0)->192.168.1.3/255.255.255.0/192.168.1.255####   level: -67  noise: -92 (25)
QFile::at: Cannot set file position 0
if(ath0)->192.168.1.3/255.255.255.0/192.168.1.255####   level: -66  noise: -91 (25)
if(ath0)->192.168.1.3/255.255.255.0/192.168.1.255####   level: -69  noise: -94 (25)
X Error: BadDevice, invalid or uninitialized input device 170
  Major opcode:  148
  Minor opcode:  3
  Resource id:  0x0
Failed to open device
X Error: BadDevice, invalid or uninitialized input device 170
  Major opcode:  148
  Minor opcode:  3
  Resource id:  0x0
Failed to open device
if(ath0)->192.168.1.3/255.255.255.0/192.168.1.255####   level: -65  noise: -90 (25)
if(ath0)->192.168.1.3/255.255.255.0/192.168.1.255####   level: -64  noise: -90 (26)