no display specified

Hi)) Then I try exec Songbird/songbird have shown this message:
Error: no display specified
If i exec Songbird/songbird-bin have shown this message:
Songbird/songbird-bin: error while loading shared libraries: libjemalloc.so: cannot open shared object file: No such file or directory
but # ls -la show this:
-rw------- 1 root audio 345 2008-11-25 01:05 application.ini
-rw------- 1 root audio 143450 2008-11-25 01:05 blocklist.xml
drwx------ 3 root audio 4096 2008-11-25 01:05 chrome
drwx------ 2 root audio 12288 2008-11-25 01:05 components
drwx------ 4 root audio 4096 2008-11-25 01:05 defaults
drwx------ 5 root audio 4096 2008-11-25 01:05 extensions
drwx------ 2 root audio 4096 2008-11-25 01:05 gst-plugins
drwx------ 2 root audio 4096 2008-11-25 01:05 jsmodules
drwx------ 2 root audio 4096 2008-11-25 01:05 lib
-rwx------ 1 root audio 30612 2008-11-25 01:05 libjemalloc.so
-rw------- 1 root audio 27425 2008-11-25 01:05 LICENSE.html
drwx------ 2 root audio 4096 2008-11-25 01:05 plugins
-rw------- 1 root audio 2932 2008-11-25 01:05 README.txt
drwx------ 2 root audio 4096 2008-11-25 01:05 scripts
drwx------ 2 root audio 4096 2008-11-25 01:05 searchplugins
-rwx------ 1 root audio 11399 2008-11-25 01:05 songbird
-rwx------ 1 root audio 27360 2008-11-25 01:05 songbird-bin
-rw------- 1 root audio 112568 2008-11-25 01:05 songbird.png
-rw------- 1 root audio 260 2008-11-25 01:05 TRADEMARK.txt
drwx------ 12 root audio 4096 2008-11-25 01:05 xulrunner

Please, help me))) Why may be this error?
PS my system: Ubuntu 8.04, all needed package installed)))