The parameters for that is stored in /etc/amavis-ng/amavis.conf but controlled by a template. You can try the alter below directly in the amavis.conf file to see that it actually solved your problem:
;; Resource limits for unpacking each message
;; How many levels of unpacking do we do?
maxlevels = 20
;; How many files do we want to write?
maxfiles = 1000
;; How much diskspace do we want to consume?
maxspace = 60M
and the afterwards change in:
/etc/e-smith/templates/etc/amavis-ng/amavis.conf/810MaxLevels
/etc/e-smith/templates/etc/amavis-ng/amavis.conf/820MaxFiles
/etc/e-smith/templates/etc/amavis-ng/amavis.conf/830MaxSpace
and expand the template with
# /sbin/e-smith/expand-template /etc/amavis-ng/amavis.conf