I searched the web and was unable to find anything that suggested that it is unsafe to plant the two next to each other, but one article said that a tomatoe juice solution is used to germinate seeds of orchids. Hope this helped http://links.jstor.org/sici?sici=000...3E2.0.CO%3B2-C
I got curious after I saw your post so I did some researching. Tomato plants sometimes have the tobacco mosaic virus and it is transferable to orchids from the tomato plant.
Here's a link of some info I found.
I dono if this is what the person you talked to meant, but somewhere in the article it said not to grow tomatoes near flowering plants.
The taboco mosaic virus is coused most tmes by a smoker who has smoked or handled cigarettes, or any tobacco for that matter, without washing their hands touches the plant. There are some plants more prone to getting this virus than others. Just another reason we should not smoke