Go to the link below and see if you can resolve the problem. I'll copy an excerpt:Known Issues
There are several known bugs that users may run into with Ubuntu 8.10 Beta. We have documented them here for your convenience along with any known workarounds.
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A problem that could result in corruption of the firmware on Intel GigE ethernet hardware has led to the disabling of the e1000e driver in the Linux kernel included in Ubuntu 8.10 Beta. Ethernet devices that use this driver cannot be used with Ubuntu 8.10 Beta; support for this hardware will be re-enabled in daily builds immediately after Beta and this issue will be resolved for the Ubuntu 8.10 final release. https://bugs.launchpad.net/bugs/263555
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Clicking on links in GNOME programs, such as evolution, will not launch firefox automatically due to a bug in a wrapper script used by the firefox-3.0 package. As a workaround, users can launch firefox manually and copy and paste links into the location bar. https://bugs.launchpad.net/bugs/275410
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NetworkManager 0.7 as included in Ubuntu 8.10 Beta is not compatible with static network configuration in /etc/network/interfaces. New installations are not affected by this issue because NetworkManager will manage all interfaces by default. Users upgrading from previous Ubuntu releases can work around this issue by disabling NetworkManager at startup. https://bugs.launchpad.net/bugs/256054
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When using the Kubuntu LiveCD, the ubiquity installer hangs at the end of the installation instead of prompting you to reboot. Investigation of this issue is ongoing; as a workaround, you can safely reboot to the new system by hand. https://bugs.launchpad.net/bugs/270423
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Installing an LTSP server fails with Ubuntu 8.10 beta because the CD is not recognized as an apt source. This will be resolved for the final release. https://bugs.launchpad.net/bugs/276349
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The Live CD's detection of nVidia hardware incorrectly selects the 'nv' driver even for hardware not supported by that driver, preventing X from running on some systems. This issue will be fixed in daily builds immediately after Beta and will be resolved for the Ubuntu 8.10 final release. https://bugs.launchpad.net/bugs/261977