Despite having auto login disabled and FileVault turned on, when sometimes logging into my mac (after sleeping) I get this happening (I've blocked out some personal info):

This then causes my mac to beach ball and lock up, at which point I have to hard reboot.
Anyone have any ideas?
System Information
- 10.7.2 ( 11C2002 )
- 2.4Ghz Intel Core i7
- 16GB 1333Mhz DDR3
- 128GB SSD from apple
- AMD Radeon HD 6770M 1GB ram
- 17-inch Late 2011
Ran memtest and got these results:
memtest all
Memtest version 4.22 (64-bit)
Copyright (C) 2004 Charles Cazabon
Copyright (C) 2004-2008 Tony Scaminaci (Macintosh port)
Licensed under the GNU General Public License version 2 only
Mac OS X 10.7.2 (11C2002) running in multiuser mode
Memory Page Size: 4096
System has 8 Intel core(s) with SSE
Requested memory: 11863MB (12440174592 bytes)
Available memory: 11863MB (12440174592 bytes)
Allocated memory: 11863MB (12440174592 bytes) at local address 0x0000000101000000
Attempting memory lock... locked successfully
Partitioning memory into 2 comparison buffers...
Buffer A: 5931MB (6220087296 bytes) starts at local address 0x0000000101000000
Buffer B: 5931MB (6220087296 bytes) starts at local address 0x0000000273bf0000
Running 1 test sequence... (CTRL-C to quit)
Test sequence 1 of 1:
Running tests on full 11863MB region...
Stuck Address : ok
Linear PRN : ok
Running comparison tests using 5931MB buffers...
Random Value : ok
Compare XOR : ok
Compare SUB : ok
Compare MUL : ok
Compare DIV : ok
Compare OR : ok
Compare AND : ok
Sequential Increment: ok
Solid Bits : ok
Block Sequential : ok
Checkerboard : ok
Bit Spread : ok
Bit Flip : ok
Walking Ones : ok
Walking Zeroes : ok
All tests passed! Execution time: 3476 seconds.