sage 4.7 does not build and run in new ubuntu 11 amd64 install!

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Hi! I had to format my computer and reinstall ubuntu 11.04 but when I reinstalled, and tried to build sage, it shows errors and when I try to click on sage, a terminal window opens for fraction of a second and closes. after that nothing happens.

I can't attach install.log, so I pasted it into internet clipboard. link text and this is written in dochtml.log and a new empty file is created with name '
?@@@8 (invalid encoding)'

/home/bhavani-shankar/apps/sage-4.7-linux-64bit-ubuntu_10.04.1_lts-x86_64-Linux/local/bin/sage-sage: line 952: /home/bhavani-shankar/apps/sage-4.7-linux-64bit-ubuntu_10.04.1_lts-x86_64-Linux/local/bin/python: cannot execute binary file

here are the first lines from install.log:

/bin/ls: cannot access bzip2-*-install: No such file or directory
/bin/ls: cannot access dir-*-install: No such file or directory
/bin/ls: cannot access prereq-*-install: No such file or directory
make[1]: Entering directory `/home/bhavani-shankar/apps/sage-4.7-linux-64bit-ubuntu_10.04.1_lts-x86_64-Linux/spkg'
standard/deps:143: warning: overriding commands for target `installed/'
standard/deps:140: warning: ignoring old commands for target `installed/'
standard/deps:146: warning: overriding commands for target `installed/'
standard/deps:143: warning: ignoring old commands for target `installed/'
make[1]: Circular installed/ <- installed/ dependency dropped.
make[1]: Circular installed/ <- installed/ dependency dropped.
make[1]: Circular installed/ <- installed/ dependency dropped.

please help!