When I cut & paste from the web to Incredimail it appears in 'Send"
and to the recipient as a long, narrow strip of text down the right
hand edge of the screen even though what was pasted is full width.

Try pasting it into a plain-text editor first; ie, Notepad, and then
into the application.

I just love metapad. It keeps your hyperlinks and such for you, but is
a great little text editor.
http://www.liquidninja.com/metapad/

try copying all the lines and every thing.

In case that text have only songle line, I use standart "start->run"
Pase and copy once again, its faster than notepad ;)