Sub Categories Not Showing in wp-admin

We are using 2.7 with great success except for one pesky issue with categories.

We have a category on our site: Honda Motorcycle Online Manuals
There is a list of sub cats named after each year of motorcycle from 2000. So we have 2000, 2001, 2002 etc. with posts associated with each.

We have another category on our site: Suzuki Motorcycle Online Manuals
When we try to create a list of years as sub cats with “Suzuki Motorcycle Online Manuals” now as the parent, the sub cats do not show up in admin tool. This means we can not put posts into these sub cats.

Is there a problem with using categories of the same name even though they are nested in different parents? Appreciate any help. I’m stuck.

Thank you.