Page 1 of DVD-r to DVD-r/w

Question is quite simply how? I have several DVD-r`s (+r`s actually) whose contents I want to put on 1 or 2 dvd+rw`s, but I don`t know how. i can only out one disc`s contents on and then get hit with a `disc contains ....do you want to erase?` message.
i always thought you would have the option to put things on after what was already there (a bit like VHS) but obviously not.
what do i do folks?
cheers.

Can you post a bit more info on a) what`s on the DVD+R`s (ie dvd video or data) and b) what software you tried (and do you have any other dvd burning software) as it is certainly possible to do what you want (well for data at least).

T.V. stuff mainly, such as Lost etc things that have lots of episodes spread over many discs. Only Software I have are DVD shrink and DVD decrypter.
thanks for any help

Check out the following guide on how to merge two titles onto one disc using DVD Shrink.
Might not be exactly what you are after but might help:

http://www.doom9.org/index.html?/mpg/dvdshrink31-main.htm