The carriage return in the text will cause the GetValue function to assume that there is a list of items, and will only return the specified item - in your case, the first paragraph. At least, this is my guess as to what is happening.
Rather than passing parameters, it might be worth your while to look into using global script variables. Since these can be seen from script to script, they can be very useful if you have a series of "objected" scripts running in sequence. Using the Set Variable script function in any of the scripts and using $$ as a prefix to make the variable or variables global, you can overcome the single parameter limitation.
You could use a different calculation, such as Position , Middle, etc. to find your parameters instead of GetValue. Then instead of using a return, you could use a pipe | symbol as divider, and use the "Position" calculation to find each occurrence as the divider.
You could use the Substitute function to remove any paragraph returns in your parameter, and replace them with an underscore or pipe symbol while you pass the parameter, then Substitute again when you pull the parameter value from the list.
For example, you want to use a list of parameters
So, the first step is to pass the parameters - Replace (parameter3 ; "¶" ; "|" ) BEFORE you list it in the parameter list
So your parameter list then looks like this instead:
Then, Substitute ( GetValue (parameterlist ; 3) ; "|" ; "¶") puts the paragraph return back into the 3rd item.
If you are using FileMaker Pro Advanced (FMPA), you could create (or borrow - see http://www.briandunning.com/filemaker-custom-functions/
a custom function that does this for you.
And of course you can have more than one $$variable at a time.
If you still want to pass the parameter.. eg from a script to a subscript... you might consider encoding the text to... say... html... then decoding inside the sub-script.
Some people use the vertical | (pipe I think it is called) to separate the values in a parameter so that parsing out the values is made simple.
Using paragraphs to separate variables can be a lot simpler but (as you discovered) it is made more dificult if you have more than one para per value.
I've attached a demo file which provides a simple illustration...
11hrg_Demo_Params.fmp12.zip 11.8 K
Useful resources for passing multiple parameters: