There has been a format change to the compiled output file. As the
CHANGELOG says:
Upgrading to v1.5 from any version prior to v1.5 requires an extra
step for people who installed gitolite using the "system install /
user setup" method described in doc/0-INSTALL.mkd. For such
installations, after the administrator has upgraded gitolite
system-wide, each "gitolite host" user must run `gl-setup` once
(without any arguments).
This is *not* an issue if you installed using src/gl-easy-install.