In case you have a problem in mounting the usb drive in linux and you have tried the conventional mount command and checked the HAL daemon(red hat) but to no avail then it is most likely that 2 drivers for the same device are installed and are interfering with each other.

You can always check that what drivers are loaded by using the dmesg command. It is likely that 2 drivers namely uhci_hcd and ehci_hcd both are installed and if that is the case then to get rid of the problem simply remove any one of the modules and usb will mount properly.

Type this command for removing the module uhci_hcd:

modprobe -r uhci_hcd (-r option for removing a module)
for more of the commands option and info type man modprobe.

after typing this command connect your usb drive and it will be mounted without hassles.

Do post your comments in case the post solved your problem.