I received the following error when installing the file at the first link:
Found existing product version: 15.6.0.0519
MUP Package contains version: 15.5.4.0423
Execute: setup.exe
Error: setup.exe exited with return code: 8
MUP finished: Tue Mar 12 23:20:08 2013
Exiting with Return Code: 8
[03/12/13 23:20:08]
--- End of Vendor Software Log ---
[03/12/13 23:20:08] Vendor Software Return Code: 8
[03/12/13 23:20:08] logo.png
[03/12/13 23:20:08] Name of Exit Code: ERROR
[03/12/13 23:20:08] Exit Code set to: 1 (0x1)
[03/12/13 23:20:08] Result: FAILURE
[03/12/13 23:20:20] Open file: C:\ProgramData\Dell\UpdatePackage\Log\Network_Driver_F1P68_WN_15.5.6.48_A04.txt