sda1 mount during installation of 11.1.

i have installed opensuse 11.1 several times on my MSI VR-320 laptop via usb/external harddrive. But somehow, while i have done it several times, i’ve encounter several error while installing it. it’s like 10 error before a succesful install. my internal 500gb harddrive holds my windows vista, while my external harddisk via usb holds my opensuse 11.1. i always take out the internal harddisk holding windows while i’m installing opensuse on the external drive. the usual error occur after i’ve set up the partition & the booting, while the installer work on deleting the existing partion & creating a new partition, be it LVM or not. the sda1 partition always “mount” while the installer either deleting, creating or formatting a partition. and an error message will pop up that the installer cannot continue because the harddrive was mounted. how can i prevent one partition to mount while opensuse is installing? it’s alway the sda1, on a LVM partition setup. the sda1 is the /boot, & it always mount during installation, & it prevent the installer to stop installing.

i cannot edit my post. the last line should be “it prevent the installer to continue.” or “it causes the installer to stop installing”