well, I figured some things out, but have another problem now. that's what I did:
* removed the hard drive which led to the errors
* booted the nas
* copied all files to an external hard drive, just to be sure that nothing goes wrong when recreating the raid (that's what took me so long to reply

)
* inserted a new, second hard drive
* recreated the raid1
* no errors or anything obviously unusual
-> so for part one I would say that one hard drive crashed and for whatever reasons the LED did not turn amber. but the status log diagnosed it sucessfully, as i can now boot up quickly wihtout the hard drive error
but, as mentioned there's a new issue:I can not login to my share anymore. I can sucessfully connect to 192.168.x.x and see the "Volume_1", "web_page" and "lp" icons, but can not go to Volume 1.
I tried it on two computers, it worked on both before:
1. Win7 Professional 64 Bit. Here I do not get an error message because I am using Offline Files. So I just see my synced Folders and the "Volume_1" folder and everything inside is marked as offline. Same behaviour with attached network drives
2. Win XP Professional 32 Bit.
Error message when clicking on the "Volume_1" folder by manually connecting to the IP via explorer:
"192.168.x.x is not accessible, you might not have permission to use this network ressource"
Error message when trying to go there via a mapped network drive:
"An Error occoured while reconnecting... An unexpected network error occured. This conenction has not been restored"Things I tried on both computers
* check if usernames/pwd are still correct in the configuration
* reconnect network drives
* check username/password combinations in credential manager (Win 7)
Any ideas what could be wrong? Thanks in advance,
philipp