Cannot save to future sessions in Custom mode

[Jonas Jarnestrom]

This bug report will be sent to the Free Software Foundation,
 not to your local site managers!!
Please write in English, because the Emacs maintainers do not have
translators to read other languages for them.

In GNU Emacs 20.6.1 (sparc-sun-solaris2.6, X toolkit)
 of Fri Mar  3 2000 on iris
configured using `configure  --with-gcc --with-pop --with-x-toolkit=lucid 
--bindir=/usr/local/bin --libexecdir=/usr/local/libexec'

Please describe exactly what actions triggered the bug
and the precise symptoms of the bug:

I enter the top level customisation window with menu command
Help->Customize->Top-level customisation group

Get a window as follows:
This is a customization buffer for group Emacs.
Square brackets show active fields; type RET or click mouse-1
on an active field to invoke its action.  Editing an option value
changes the text in the buffer; invoke the State button and
choose the Set operation to set the option value.
Invoke [Help] for more information.

Operate on everything in this buffer:
 [Set for Current Session] [Save for Future Sessions]
 [Reset] [Reset to Saved] [Reset to Standard]   [Bury Buffer]

<snipped>

When I click on the [Save for Future Sessions] field with mouse-2
I get the scan error below.
Is this a general fault or is it me who have done something naughty?

/Jonas Järneström




Recent messages:
Scan error: "Unbalanced parentheses", 259, 445 [17 times]
Auto-saving...
Scan error: "Unbalanced parentheses", 259, 445 [2 times]
Creating group...
Creating group...done
Scan error: "Unbalanced parentheses", 259, 445 [2 times]
Beginning of buffer [2 times]
Scan error: "Unbalanced parentheses", 259, 445
Quit
Type C-x 1 to remove help window.  M-C-v to scroll the help.