Fedora :: Unable To Re Read Sda When Gparted

I have the following problem on fedora 12, x64 amd; I have installed fedora 12 from a live cd, whit custum partition tables (no lvm or somting like that). my sceam is (on a single 80 gb maxtor sata disk only 1 system, clean install):

/
/home
swap

Notitng more (not needed also). The installation was successfully. No problems on the install part. ALs no problems on the ugprade part. I installed the rest using yum groupinstall. When i want to add the extra 4 disks (all samsung 1 tb spinpoint sata) that i have for my backupdata, non of the partiotionprograms can recognise. If i do; moun /dev/sdb1/ /media/sdb1, it says that i need to add the file system. well, by some sort of misstake, i could find a workaround for this. When start gparted, select on of the samsung disks, select any of the flags in gpart, remove the flag and give it a ok, gpart can read the amount of data thats used. After that i ame able to mount whit a simple mount /dev/sbd1 /media/sdb1 command. When i use this command: hdparm -z /dev/sdb1, i can mount the disk afterwards, whitout problems. Of course, i need to add them als to my /etc/fstab file, so they automount each time at boot.........