I can see but not open my external hard disk in the backup? I use Time capsualup

I am not sure what you mean.

I have two extarnal hard disks connected to my powerbook. Both are backing up with Time Capsule.

But one of them are grey, I can see it but not open it in the back up?

Somebody that know what to do?

Time Capsule is the hardware router which has an inbuilt hard disk for Time Machine backups.

Do you mean you are using Time Machine to backup the external drives to the Time Capsule?

If not Time Capsule what is the target??

But one of them are grey

Where is it grey?

Is it formatted Mac OS extended Journaled because TM can only backup HFS+ disks.

Please show us a screen shot of the setup of TM and that the two external drives are included in the backup.

Please install the widget so you can see what is going on per the TM log.

A1 here.

http://pondini.org/TM/Troubleshooting.html