The bigfloat expt function errors on (0.75b0 + 1.5b0*%i)^(%i/4):
$ ./maxima-local
Maxima 5.30post http://maxima.sourceforge.net using Lisp Clozure Common Lisp Version 1.9-r15764 (WindowsX8632)
(%i1) x : 0.75b0 + %i * 1.5b0$
(%i2) a : %i/4$
(%i3) to_lisp();
MAXIMA> (bigfloat::expt (bigfloat::to (meval '$x)) (bigfloat::to (meval '$a)))
Maxima encountered a Lisp error: DIVISION-BY-ZERO detected performing LOG on (0.0)
Changing a to bfloat(%i/4) eliminates the problem:
MAXIMA> (bigfloat::expt (bigfloat::to (meval '$x)) (bigfloat::to (meval '$a)))
+7.518905433525544b-1+9.773370293667246b-2*%i
--Barton