bug in solve



As I try to run the following commands, the result is

(C1) Solve((a^2+1)*x^2+a*x+a=0,x);
quotient is not exact
 -- an error.  Quitting.  To debug this try DEBUGMODE(TRUE);)

(C2) Solve((a^2+1)*x^2+a*x+a^2=0,x);
 (Solves OK)

(C3) Solve((a^2+1)*x^2+a^2*x+a^2=0,x);
quotient is not exact
 -- an error.  Quitting.  To debug this try DEBUGMODE(TRUE);)

(C4) Solve((a^3+1)*x^2+a^2*x+1=0,x);
Quotient by a polynomial of higher degree
 -- an error.  Quitting.  To debug this try DEBUGMODE(TRUE);)

(C5) Solve((a^2+1)*x^2+a*x+a^5=0,x);
 (Solves OK)

(C6) Solve((a^2+1)*x^2+a^3*x+1=0,x);

And the last one hangs maxima, I have to use ^C to get back.

Can someone please tell me what's going on?

I'm using 
maxima_5.6-12.deb

jt@Bachue:~$ uname -a
Linux Bachue 2.4.8 #11 Sun Sep 23 11:23:51 COT 2001 i686 unknown

on a Dell Dimension 8100.

I run the rtest*.mac and all went fine.

Jurgen