I have typed a recursive chmod o-rwx command from root in a linux via ssh. After that I can not login as root anymore. It is a huge problem now. Can I do anything to do to resolve this? I can only work via ssh, not locally.
This isn't the answer you want to hear, but I'm afraid you've hosed that box. If you can't ssh in now then you will need local hands-and-eyes to try to get some kind of access, and that will probably just be to save what data you can before you reinstall and restore the box from backups.
You do have backups, don't you?
Repermissioning an entire operating system without excellent backups isn't a trivial option even for experts, and doing it remotely is something I'd seriously quake at, even with 20+ years sysadminning under my belt.
I think you have no real choice but to own up to whoever that you've hosed the box, and either get on a plane and go visit it for an extended period of nursing it back to life, or just count it lost and move on; probably whichever is cheapest.
What you can do is learn from this:
It seems like the end of the world right now, but most of us have done something boneheaded like this at one point or another. It's a test of character: if you can be honest with everyone else now, and honest with yourself going forwards so you learn from it, then it's not quite as bad a disaster as it seems to be today.
Is there anything still running on the box, such as a web service or email service?
Some services may have the ability to change ownerships for you. cPanel or webmin may still work if you have them installed. I'm not sure how these would be affected by your recursive chmod but it's worth looking.
If you have services running that do not have this functionality, you may still be able to force them into it. This option is not for the faint of heart. I'm talking about hacking your own box here. Find an exploit from somewhere like Exploit DB and use it to gain a shell and fix the necessary permissions. This may not be possible for a bunch of different classes of reasons and it has the potential to make the situation worse.
My vote would still be to get your hosting provider to do it for you with a LiveCD.
Ask support to recover setuid bit on /bin/login, /bin/su, sudo That will let you login as root. Local support can boot the server into single-user mode without root password. They have to know boot loader password, if there's one.
When you're logged back, run