"System error: caught fatal error" with both FORTRAN and TeX output

Dear All,

The following input file causes Axiom to produce the "System error:
Caught fatal error [memory may be damaged]" message.  If it's the
first part of a longer input file, )read then fails to execute the
remainder of the input file.  The error appears to be related to the
attempt to produce both TeX and FORTRAN output - getting rid of either
makes the error message go away.  Any ideas what's going on, please?

Regards,

Dan

)set output fortran outfile
)set output fortran on
)set output tex outfile
)set output tex on

l:Union(Variable l,Integer)
m:Union(Variable m,Integer)
n:Union(Variable n,Integer)

A1 := A10*sin(l*%pi*x)*cos(m*%pi*y)*cos(n*%pi*z)
B1 := B10*cos(l*%pi*x)*sin(m*%pi*y)*cos(n*%pi*z)
C1 := C10*cos(l*%pi*x)*cos(m*%pi*y)*sin(n*%pi*z)
D1 := D10*cos(l*%pi*x)*cos(m*%pi*y)*sin(n*%pi*z)

A2 := A20*sin(l*%pi*x)*cos(m*%pi*y)*cos(n*%pi*z)+A22*sin(2*l*%pi*x)*cos(2*n*%pi*z)
B2 := B20*cos(l*%pi*x)*sin(m*%pi*y)*cos(n*%pi*z)+B23*sin(2*m*%pi*y)*cos(2*n*%pi*z)
C2 := C20*cos(l*%pi*x)*cos(m*%pi*y)*sin(n*%pi*z)+(C21+C22*cos(2*l*%pi*x)+C23*cos(2*m*%pi*y))*sin(2*n*%pi*z)
D2 := D20*cos(l*%pi*x)*cos(m*%pi*y)*sin(n*%pi*z)+(D21+D22*cos(2*l*%pi*x)+D23*cos(2*m*%pi*y))*sin(2*n*%pi*z)

term01 := cos(%pi*l*x)*cos(%pi*m*y)*sin(%pi*n*z)
term02 := cos(3*%pi*l*x)*cos(%pi*m*y)*sin(%pi*n*z)
term03 := cos(%pi*l*x)*cos(3*%pi*m*y)*sin(%pi*n*z)
term04 := sin(2*%pi*n*z)
term05 := cos(2*%pi*l*x)*sin(2*%pi*n*z)
term06 := cos(2*%pi*m*y)*sin(2*%pi*n*z)
term07 := cos(2*%pi*l*x)*cos(2*%pi*m*y)*sin(2*%pi*n*z)
term08 := cos(%pi*l*x)*cos(%pi*m*y)*sin(3*%pi*n*z)
term09 := cos(3*%pi*l*x)*cos(%pi*m*y)*sin(3*%pi*n*z)
term10 := cos(%pi*l*x)*cos(3*%pi*m*y)*sin(3*%pi*n*z)

C3 := C301*term01+C302*term02+C303*term03+C304*term04+C305*term05+C306*term06+C307*term07+C308*term08+C309*term09+C310*term10
D3 := D301*term01+D302*term02+D303*term03+D304*term04+D305*term05+D306*term06+D307*term07+D308*term08+D309*term09+D310*term10

differentialequation := A1*differentiate(D2,x)+B1*differentiate(D2,y)+C1*differentiate(D2,z)+A2*differentiate(D1,x)+B2*differentiate(D1,y)+C2*differentiate(D1,z)-C3-differentiate(D3,x,2)-differentiate(D3,y,2)-differentiate(D3,z,2) = 0