NOT reproducible with "Ooo 3.1.1 WIN XP DE[OOO310m19 (Build 9420)]"!
Mac specific?

@dcnicholls:
Please contribute a clear step by step instruction containing all observations
(error messages ...), _every_key_press_and_every_mouse_click_ how to reproduce
the problem.

Here's the sequence:

Create a .csv text file with a one line entry 'fred,1' (I used the Mac program textedit.app to do this)
Open it in Open Office Calc.
Save it as a Microsoft Excel 97/... .csv file
Select the second cell containing the numeral '1'
In the Input Line slot, select the numeral '1' using the mouse
Click on the hyperink icon in the tool bar
Enter the URL 'http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?objname=HIPASS+J0107%2B01'
Click Apply
Select another cell with the mouse then click on the newly created hyperlink
You will find that the URL it opens is 'http://nedwww.ipac.caltech.edu/cgi-bin/nph-objsearch?
objname=HIPASS+J0107+01'
ie it has converted the percent-2-B to '+'

No error messages, just an unrequested ASCII character conversion.

I might add that the same result happens whether you type or paste the URL into the hyperlink window; 
and that I use textedit.app in pure text mode, not RTF.

In the case of these two URLS, the correct one works and the one with the substituted ASCII char breaks on 
the website in question

Reproduced with 3.2.1 and 3.3.0 running on Windows 7 and XP.

Steps to reproduce:
1: Copy the URL provided by dcnicholls
2: Go to Insert -> Hyperlink
3: Paste the copied URL into the "Target" input box, press Apply and close
   the dialog box. 
4: Execute the link and a wrong page is shown
5: Select the link and go to Insert -> Hyperlink
6: Check the URL in the "Target" input box to see "%2B" is converted to "+"

Work around:
* Enable "Automatic URL Recognition" and paste the URL into a cell.
  Auto replaced link works ok and "%2B" remains as is w/o being replaced.
* Use "Push Button" from "Form Controls" and use its
  "Open document/web page" function.

I believe it's to do with the character encoding used when converting
texts into a hyperlink at Hyperlink dialog box. Also reproducible with
Writer and Impress.

Sorry for the double post.

I forgot to add that I could reproduce the bug on newly created OOo files.
Tested with Calc, Writer and Impress. All tests came out positive and could
reproduce every time with the given steps.

This Issue requires more information ('needmoreinfo'), but has not been updated
within the last year. Please provide feedback as requested and re-test with the the latest version of OpenOffice - the problem(s) may already be addressed. 

You can download Apache OpenOffice 3.4.1 from http://www.openoffice.org/download

Please report back the outcome of your testing, so this Issue may be closed or
progressed as necessary - otherwise the issue may be Resolved as Invalid in the
future.

Sorry, I no longer use Open Office.  If you're unable to test the bug from my detailed description, I suggest the bug be closed.

Just pasting URL in cell should work it around.
Also, all the necessary information have already been given.

This is a genuine bug if it still occurs.  That should be verified.

The "+" character is reserved as a sub-delimiter and it must be escaped (%-encoded) when a delimiter purpose is not intended for it.  Since only the person entering the URI can know the correct intention, %-encoded reserved characters should never be un-encoded by OpenOffice, especially for a URI that is destined to something external to the document.

(This explained in RFC3986 section 2.4 and the inclusion of "+" as a sub-delimiter and reserved character is in section 2.2. 

This needs to be confirmed.

As given in comment 4.

Rev. 1503704 Win 7