The "Post your Striped Roses Here" post is on page 4 in the gallery. When I got the Whoops error after clicking the link for this under search, I noticed the date of that recent post was May 11. So tho the link no longer works you can click on past pages in the garden gallery based on dates listed in search results. A little guesswork and trial and error but it works.

Look in the address bar when you get error. If the URL of the page where you get the "Whoops" starts with "forums2.gardenweb..." then go up to the address bar and remove the '2' so that the address has "forums.gardenweb...". Then hit enter.

Oh thank you! Now I can really enable my boss. He loves my roses and wants me to help him choose some red/white roses.