plot2d in maxima 5.6



Hi
I know the topic must have been raised previously, but considering the 
inexistence of a search engine in maxima's www for the list archives, i could 
not find references of the same nature as this.

It is about apparent bugs in plot2d, called from maxima 5.6 ; i have noticed 
it on two different computers using the same maxima version, both compiled 
with the same GCL. Here it is :
-> "plot2d(x^2,[x,0,4]);" performs fine
-> "plot2d(log(x),[x,1,4]);" also
-> "plot2d(log(x),[x,0,4]);" returns the following error :

LOG(0) has been generated.
 -- an error.  Quitting.  To debug this try DEBUGMODE(TRUE);)

There seems to be the same kind of trouble with some other functions.

Here is my question : Has the issue been discussed before ? Is it inherent to 
plot2d in all maxima versions, or is it specific to a certain software 
configuration / maxima version ?

Thank you all very much !
-- 
Michael Mestre
The elder trees stand restlessly along the brand new streetways
//////+