Ubuntu 11.04 was released today, but it seems the much anticipated version has a minor bug which makes it difficult for users to install the version.
When we attempted to install Ubuntu via the Live version, we were not able to enter any text in the mount point box of the partitioning section.
Update: Swapnil just verified with the Ubuntu team and they have confirmed the bug. It is documented in the release note:
The manual mount point entry box in the desktop installer's partitioner does not accept keyboard input. The drop-down still works, so various standard mount points may be selected, but custom ones cannot. This was noticed too late to be corrected for 11.04. In the meantime, you can mount partitions manually later, or use the alternate install CD. (769043)
The team is suggesting to use the alternate CD method to install Ubuntu 11.04. You can download the alternate CD from here. However, the alternate CD has a non-graphical installer which makes it is a bit tricky for novice users.
The best solution would be to install the OS using the LiveCD, without mounting the partitions during the installation. You can mount the partitions later, once you have the new Ubuntu installed. Muktware has published a blog about how to mount your partitions after installting Ubuntu 11.04
We have created a comprehensive manual to assist you in installing, or upgrading to, the Ubuntu 11.04. Check out the complete manual here. Muktware's Ubuntu Manual