here is the solution.
there were quite a few posts on the topic where people could not find a driver for the PCI SYSTEM MANAGEMENT BUS. but no helpful answer.

i was trying to post a followup to one of the messages but the system didnīt let me post since it was too old. anyhow, i did not want to waste the answer that i already wrote. so here it is... just as a new post :)

after a looong time trying to solve the same problem i finally found the solution today.

the required drivers are the drivers for the chipset on your motherboard.

to fix this problem you need to look at your motherboard and check who the manufacturer of your chipset is. (no not the CPU! the chipset on your motherboard. if you do not know what i am talking about then search for some info on "chipset" somewhere else first.)

in my case it was an intel chipset.
in case yours is also intel just go to www.intel.com and look for
chipset > support for chipsets. there you will find even a utility to identify the chipset on your board. get it. after you have the required info download the inf file for your chipset, install it, reboot and you are all done.

hope i could help someone ;)

The Pci system management bus - solution worked like a charm. I am grateful!

well, i'm glad it worked for someone, cause unfortunately, it didnt work for me..

Heres my story...
I have a HP pavilion, virus made me wipe my system, so the recovery disks won't work, and HP being the helpful company it is, did nothing...
I"ve downloaded the newest drivers etc for my onboard sound and video.. those are the only drivers available..
(my video chipset by the way is i810 intel)
I still get the pci management bus problem.. now just to make sure, thats why it will not connect to the internet through my pci network card right? it sees and detected the network card, but won't connect to the internet..
I know the card works etc because I have the hd partitioned with linux on the other and it works fine..