installing 5.1-RELEASE - problem with swap

[Prestele Stefan]

Hi all,                                                                         
                                                                                
I'm trying to install the 5.1-RELEASE. But after defining my partitions with    
disklabel I get an error, that he can't find device node /dev/ad0s1b -          
my swap partition. How can this be? I know that in FreeBSD 5.x you don't        
have to create device nodes by yourself as DEVFS is used for this...?           
                                                                                
How to solve this problem?                                                      
                                                                                
THX