Quicker Method! - Tested in Windows XP
To resolve the problem, type this command from Start, Run dialog:
IE4UINIT.EXE
The above command creates the Quick Launch folder automatically, if it is missing in the above location. Now, try to enable the Quick Launch bar. If the same error occurs, it's caused by another issue (due to a spyware removal), type these two commands:
REGSVR32 /i SHELL32.DLL
REGSVR32 /i BROWSEUI.DLL
Restart Windows and enable the Quick Launch Toolbar.