I've been googling this a lot but haven't found a (working) solution yet. I did find a link to what could be a solution, but the link is not working anymore.
I'm an IT guy in an office where we have a small team of four people using Adobe Creative Suite 4. Recently they contacted me asking for help because Kuler was no longer working for them (it stopped working for all four).
I installed InDesign CS4 on my own machine only to see that it does not work for me either. The error message is "No internet connection detected. Your computer must be online in order to search or access kuler themes".
When I go to Windows -> Extensions -> Connections I'm able to login, but not able to search for updates, I just get "The update server is unavailable".
When running the Kuler Air app I just get "kuler klash, please try again later".
Because we're a big company we do of course have antivirus and firewalls. To make sure that the problem isn't because of this I installed InDesign on a machine (server) on a completely different network with less strict firewall and no antivirus on the machine, but It's just the same error message as before.
Our machines are running Windows 7 Enterprise (the extra test was done on a Windows 2012 Server).
Is Kuler just not working for CS4 anymore?
Looking forward to a clarification on this problem.
The Kuler team recently rebuilt the backend of the Kuler service for security, maintenance, and peformance reasons. (the old back-end was showing signs of failure).
Anyway, it seems the new backend is not working with old Kuler APIs (CS3, CS4, and the air app and mac widget). Adobe typically provides support for up to two versions back. At the moment, that's CS5 or newer. So, I'm afraid it's not likely that you can expect a fix for CS4.
At this point, your team can use the web application to browse, create, and search themes. They can also download themes as ASE files (on the website) to import into InDesign CS4.