The most recent update to samba-client, which provides the files mount.cifs and umount.cifs crippled the ability of those two commands to be run as a regular user, either by changing permissions or using set userID. Refer to this thread
for a bit more information about this.
At least one user in that thread downgraded a couple of the samba packages to the previous version in order for his scripts (run as regular user) to continue to work to "mount.cifs" windows shares. I also have a script that I run as a regular user that calls "mount.cifs", which no longer worked after the update.
My solution was not to downgrade the samba packages, but to download the previous version of samba-client, extract the rpm package using rpmdev-extract into a folder in my home directory and then copy mount.cifs and umount.cifs from there into /usr/local/bin/, changing both to set userID (chmod 4755 /usr/local/bin/mount.cifs), and edit my script to call /usr/local/bin/mount.cifs instead of /sbin/mount.cifs..