Gnuplot And Xcode

there was indeed a problem with my environment.plist file. Seems like I had accidentally saved it as .rtf instead of .txt before I changed the extension to .plist. It had a RTF preamble that did not show up in TextEdit, but was obvious when I opened the file with BBEdit. Stupid me. Anyway, works fine now.

Thanks a lot for your help!
Hello, :)
I've the same problem with XCode and gnuplot_i ...
When I try to run my program (in C++) I get
terminate called after throwing an instance of 'GnuplotException'
what(): cannot find DISPLAY variable
My gnuplot works well with Aquaterm; I tried to follow the instructions in this thread about the file environment.plist but nothing changes.
Is it possible the reason is I installed gnuplot using fink? Could be I don't write the right adress in environment.plist?
Please help me!

You will need to edit the .plist file originally posted by Viro so that it links to where fink stores the binary files. If I remember correctly fink would put it in /sw/bin so try this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "
<plist version="1.0">

Make sure this text is saved as a .txt and not an .rtf, name/save it here:
Hi, thx you very much! ;)
I already did what you say. At the beginning all worked fine, but after few compilations and little changes Xcode began to have a problem in every project (also the easiest, also "Hello world!"): Xcode didn't compile and the error was always:
fatal error: error writing to -: Broken pipe
(Note that g++ from the Terminal did compile correctly at that time)
I resolved (for now) this problem thanks to the of Jack Repenning from the XCode Mail List in Apple site this morning... I post what he said to do if it will help someone other for the future:
1. Note down the PATH settings you presently have (which, we suspect, do not include /usr/bin)
2. in Terminal, move this environment.plist aside, say
mv ~/.MacOSX/environment.plist ~/.MacOSX/environment-save.plist
3. log out, log back in (necessary because this file is read during login)
4. in Terminal, "echo $PATH", thereby learning what your $PATH ought to look like
5. put environment.plist back, say
mv ~/.MacOSX/environment-save.plist ~/.MacOSX/environment.plist
6. open it again, as before
7. put whatever you got in step 4 at the front of the PATH setting, being careful to separate it from the evil stuff that apparently came from gnuplot with a colon (":").
8. log out and back in again
9. everybody ought to be happy
After I did these things Xcode returned to work well with the interface gnuplot_i too...