We've checked and the zimlets are deployed by CoS on their servers.
The webex zimlet does not work with 5.0.x anyway, see :
Bug 21799 – Webex zimlet works partially and
Bug 27906 – WebEx Zimlet error
The Yahoo!Maps zimlet has several issues too (in ZCS <5.0.7), see :
Bug 28287 – Zimlet "Maps" does not work
The starxpert zimlet should not be working with 4.5.11 while it seems it does, wrong zimlet version ?