formatting

["J j" <italian_spike@xxxxxxxxxxx>]

when i install freebsd and partition my hard drive slice and then go to 
format i get an error and it says that it can't format the filesystem and it 
gives this error:

unable to make root filesystem
command return status 36 on /dev/ad0s3a

i thought it might be a bad iso image so i downloaded it again and had the 
same problem. my HD is a maxtor slimline 40GB