Hi I found this problem with factor: modulus:197; factor(x^51+x^22+1); " Maxima encountered a Lisp error: Error during processing of --eval option "(cl-user::run)": Argument X is not a NUMBER: NIL Automatically continuing. To reenable the Lisp debugger set *debugger-hook* to nil. " Remark: I am using 5.10.99rc2 with sbcl. compiled for Ubuntu. Fabrizio