Steam doesn't allow me to choose another Steam Library folder when installing CS:S (it doesn't show the drop-down list).

System information:

Processor Information:
Vendor:  GenuineIntel
Speed: 3301 Mhz
4 logical processors
4 physical processors
HyperThreading:  Unsupported
FCMOV:  Supported
SSE2:  Supported
SSE3:  Supported
SSSE3:  Supported
SSE4a:  Unsupported
SSE41:  Supported
SSE42:  Supported

Network Information:
Network Speed:  

Operating System Version:
Linux (64 bit)
Kernel Name:  Linux
Kernel Version:  3.7.5-1-ARCH
X Server vendor:  The X.Org Foundation
X Server release:  11302000

Video Card:
Driver:  X.Org Gallium 0.4 on AMD RV710

Driver Version:  3.0 Mesa 9.0.2
Desktop Color Depth: 24 bits per pixel
Monitor Refresh Rate: 59 Hz
VendorID:  0x1002
DeviceID:  0x954f
Number of Monitors:  1
Number of Logical Video Cards:  1
Primary Display Resolution:  1920 x 1080
Desktop Resolution: 1920 x 1080
Primary Display Size: 20,08" x 11,42"  (23,07" diag)
                                        51,0cm x 29,0cm  (58,6cm diag)
Primary VRAM Not Detected

Sound card:
Audio device: Realtek ALC898

Memory:
RAM:  7884 Mb

Miscellaneous:
UI Language:  English
LANG:  de_DE.utf8
Microphone:  Not set
Total Hard Disk Space Available:  24433 Mb
Largest Free Hard Disk Block:  13739 Mb

Installed software:

Recent Failure Reports: