Can't Format

[ozzyboy]

i want to instal 10.4.7 and I cant format my partition
I make a picture with error:
http://att.macrumors.com/attachment.php?attachmentid=83094&stc=1&d=1187818908

 

[kolax]

More information required - what version of OSX are you on right now that you want to install 10.4.7?

Are you trying to format the Mac partition with the computer loaded into OSX? It won't let you. You need to restart the computer and boot from your installation disc.

 

[ozzyboy]

yap that's right :| ...os x 10.4.7 and I tryed to format under instalation disk, with disk utillities from instaltion disk...
in the past I was formatting 3-4 times and I haven't no problems. right now I cant explain what is the problem...
the partition is primary and active and it has 20Gb...