Please update nginx on EPEL-5 to latest release (0.7.65).
EL-5 was release initially with the 0.6 branch. I have not updated to 0.7 because I think it would go against the EPEL Guidlines and Policies (https://fedoraproject.org/wiki/EPEL/GuidelinesAndPolicies#Some_examples_of_what_package_updates_that_are_fine_or_not)
I did update EL-4 to nginx 0.6 when nginx 0.5 was declared unsupported.
EL-6 will be nginx stable at the time it is released. This will most likely be 0.7 unless 0.8 is the new stable before EL-6 is released.