[Appointments+] Either php curl is not installed or HTTPS wrappers are not enabled.

I am getting the above error message after upgrading to latest Appointments+, even though I most definitely DO have Curl installed. When I login to shell and try to install it, I get this message:

root@big:~# sudo apt-get install curl
Reading package lists... Done
Building dependency tree
Reading state information... Done
curl is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

I can't sync with Google cal and I need to ASAP. Thanks.