Just open a command prompt then and do svn co with the path you gave. Unless you are in a country or have a provider with restricted internet idiocy you should be ok.
I double checked right now. Both Tortoise and plain svn work as they should from the Netherlands.
Even stranger is that he says he can check out trunk, just not branches/fixes_1_8.
@BobS: Are you sure that you are using same path prefix for branches/fixes_1_8 that you are using for trunk?
Please do this:
- Right-click on your local folder where you checked out the trunk
- from pop-up menu choose "Tortoise SVN", then "Repo-browser"
- Now Repository browser should appear. Wait until it gets filled with paths from repository. Then, in the left side tree view, can you see the "branches" folder (see attached picture Capture1)?
If you can, expand branches and fixes (see Capture2). Copy the path from URL window from top and try checkout with this...