problem with the use of macports os x lion

[François Laenen]

Hello,

I'm feeling a bit desperate since I updated for Mac Os X Lion 10.7, just because the extraction process, the "tar" command, does not work anymore because it's a powerpc command!
And this applies also with macports: when I install it from the dmg disk, the one for Lion, it says at the end of the installation that the tar command couldn't launch!
Hopefully, I can download the source, extract it with another utility, then install macports with source, this seems to work. 
But I can't install any port or performing a "selfupdate":

When I try to install a port, the problem is:

Error: Target org.macports.extract returned: shell command failed (see log for details)

When I try to selfupdate with sudo port -v selfupdate , the problem is: 

Launch of "tar" failed: the PowerPC architecture is no longer supported.

I've got the latest version of Xcode and macports, this is not the problem.

Can you help me with this issue?

Many thanks,

François