[GAP Forum] problem with help viewer -- no longer uses xpdf

[mike newman]

Hello,

I am suddenly no longer able to use the GAP help viewer in xpdf mode; 
it only offers help in "screen" mode.
I'm not sure exactly when this happened, but it has definitely 
been working with xpdf before (and for a long time).

I currently have
    SetHelpViewer("xpdf");
in my .gaprc

Just to make sure, after I start gap I can try:
    gap> SetHelpViewer();
    #I  Trying to use
    #I  [ "xpdf", "screen" ]
    #I  (in this order) as help viewer.
which looks correct to me.

I have tried SetHelpViewer("acroread");, and have also tried 
re-executing these commands in GAP (as opposed to just in the .gaprc). 
In all cases help files come up as per "screen".
So if I type (for instance)
    gap> ?list
I get text within GAP, as opposed to xpdf in another window.

By the way, xpdf and acroread are both installed on my system, and in 
copious use for some time.  For what it's worth I am running ubuntu, 
version 10.4.

If anyone has encountered this and knows what's going on I would 
appreciate hearing from you!

Thanks in advance.

--mike