I've just spent an entire late night banging my head against one of SharePoint's less-than-helpful error messages.
I was creating a list with about 30 text fields. The names of the fields are all pretty verbose. When I deployed the list template and tried to create an instance of it (or when creating the list instance through our content deployment tool), I got the following error in the SharePoint log:
Failed to do column assignments for list "MyList" for web http://dev04/en/subsite, Feature 35A5B190-D760-46eb-90C9-4F56CBB3990E, Template Id 100113.
I did a quick Google search on the error, and turned up one blog entry which said "don't specify the ColName attribute in the list definition." That wasn't my case.
After a bunch of trial and error, I found that two of my columns had the same name (the "Name" attribute). The GUIDs were all distinct, so that was okay — but Sharepoint can't handle duplicate names (but doesn't validate that or give you helpful error messages).
Once I changed the second name, everything worked fine.