I haven't used CWM in some time, but I strongly suspect that the poster above is correct. That it may simply be that CWM doesn't fully support the S5 at this time. You can do a forum search for the CWM support thread and no doubt find more information about the status there.
TWRP does support the S5 properly.. well maybe not encryption, but everything else. And lots of posters have stated that Philz is working fine on the S5 as well.