I see the same thing with SBCL and Clisp using git HEAD:

(%i1) build_info();

(%o1)

Maxima version: "branch_5_33_base_149_g1a9bc94"

Maxima build date: "2014-07-13 11:34:44"

Host type: "x86_64-unknown-linux-gnu"

Lisp implementation type: "SBCL"

Lisp implementation version: "1.2.0.debian"

(%i2) load(abs_integrate)$

STYLE-WARNING: redefining MAXIMA::OPAPPLY in DEFMACRO

STYLE-WARNING: redefining MAXIMA::OPCONS in DEFMACRO

(%i3) f: diff((tan(x)+x)*exp(tan(x)),x)$

(%i4) integrate(f,x);

Maxima encountered a Lisp error:

The value 0 is not of type LIST.

(%i1) build_info();

(%o1)

Maxima version: "branch_5_33_base_149_g1a9bc94"

Maxima build date: "2014-07-13 11:34:43"

Host type: "x86_64-unknown-linux-gnu"

Lisp implementation type: "CLISP"

Lisp implementation version: "2.49 (2010-07-07) (built 3611082867) (memory 3614258085)"

(%i2) load(abs_integrate)$

WARNING: DEFUN/DEFMACRO: redefining macro OPAPPLY in /media/disk1part7/maxima/maxima-code/share/fourier_elim/fourier_elim.lisp, was defined in

/media/disk1part7/maxima/maxima-code/share/to_poly_solve/to_poly.lisp

WARNING: DEFUN/DEFMACRO: redefining macro OPCONS in /media/disk1part7/maxima/maxima-code/share/fourier_elim/fourier_elim.lisp, was defined in

/media/disk1part7/maxima/maxima-code/src/binary-clisp/nummod.fas

(%i3) f: diff((tan(x)+x)*exp(tan(x)),x)$

(%i4) integrate(f,x);

Maxima encountered a Lisp error:

CAR: 0 is not a list