Delete objectClass from DN

OpenLDAP 2.4.16 on CentOS 5.3
Perl version 5.10.0 on Ubuntu

I Have this entry in LDAP:

dn: cn=00-1E-52-76-B4-8A,ou=Devices,ou=Network,dc=mbl,dc=edu
cn: 00-1E-52-76-B4-8A
userPassword:: <secret>
radiusExpiration: 2030123100:00:00
radiusCheckItem: 999993
radiusUserCategory: FIXED
description: Fred Mertz
macAddress: 00:1E:52:76:B4:8A
ipHostNumber: 128.128.164.100
objectClass: radiusprofile
objectClass: simpleSecurityObject
objectClass: device
objectClass: ieee802Device
objectClass: ipHost
radiusFilterId: Enterasys:version=1:policy=A-User

I want to delete the objectClass 'ipHost' and attribute
'ipHostNumber'. What is the perl code to do this? Everything I've read
is geared towards add/replace/delete attribute -> value but not
objectClass.

$mesg = $obj->modify($dn,
                changes => [
                delete => [ 'objectclass' => [ 'ipHost' ]],
                ]
                );

Returns:
error 65 - The request specifies a change to an existing entry or the
addition of a new
entry that does not comply with the servers schema