Installing Drupal Ubercart and getting to work can be a real drag especially with all the error popping up. White screens of death, MySQL 'has gone away' errors, sudden inability to access any pages at all, etc. My advice is don't give up. Here are some tips:

• Drupal Ubercart has many conflicts, for example with Related Items module. If you want Ubercart, backup your site, start with the Ubercart modules first, get it working and then install the others.

• And enable one module at a time, so that conflicts are identifiable. The moment you have white screen of death or mysql errors taking over your screen, disable the last module that you've enable. And if you cannot do so, use cpanel and delete or move the folder else where.

• Its vital that you back up your database often as possible so that you can always restore the latest backup when you run into problems.

• If there's an seemingly unsolveable problem, just do a fresh extract of Drupal, copy the default/files and all/themes folder to your working drupal, and if necessary, point the settings.php to your exisiting database. But DO NOT copy your modules folder, coz thats the  one causing the problems. Install the modules one by one, and make sure to get the latest editions of the contributed modules.

• Remember, modules with a 'alpha' or 'dev' or 'beta' are not really stable yet, so always look to removing these modules to solve issues. Also don't just ignore that message that tells you to 'update' you installation. It actually has found some new and stable editions of the modules that you are using.

One minor issue that i faced was that drupal ubercart products has no category selection. This was easily solved by going to Taxonomy -> 'edit Vocabulary' and tick both the 'Product' and 'Product Kit'. Only then the category selection box appears. If there's anything that doesn't make sense, please register and post the question at the comments and I'll be glad to help out.