Big problem with external drives after 10.5.4

Hello i have hudge problem with mounting external drives. on leopard
I search through apple sites and forums and seems that there is no solution.
The problem is like that:
after last update to 10.5.4 i cant mount any external drive, i plug it in, and nothing happens. Mac doesnt see them, until i restart the system with drive plugged in. After restart drive is working corectly, but if i turn if off or unmount it then the story begins and i have to restart comp again if i need to mount it.

the problem is maybe not crucial but heavyly annoying, when every pendrive or photo camera has to be mounted by reseting the computer. The funny thing is that just afer reboot i can plug something in and then OsX sees it, it works just for about a minute and then the story begins again and again... restart and restart. and nothing can mount after a minute after res.

I tryed to resolve this problem by repairing permissions with disc utility and OnyX, I tryed to use the combo upgrade to 10.5.4. but the package says that i cant install it [maybe because im already 10.5.4] Nothing helps.
Now im stuck with this problem, nothing helps.

Please help or just show me some tips or the way to solution. its very annoying, im working as an editor, and everytime i have to use ext. drive or even just simple pendrive: restart. sucks very much. And i dont want to reinstal system

pls pm or email me or just post answer.

Just checking you are dragging the external drive icon to trash before unmounting? Save as with PC's just disconnecting can cause corruption problems.

yes, that is not the case, im doing everyting as im supposed to do with icons etc.
problem is that to mount the drive i have reboot the system

Using firewire I take it? If so try using a different cable.

dang, again its not the matter of cable, any external doesnt work, usb, firewire, photo cameras, film cameras. just everything that contains outside memory.