Please always search prior to creating new threads. http://en.forums.wordpress.com/tags/can039t-add-links This is an issue that others have been experiencing and that Staff are working to resolve. They require your assistance to resolve it so please undertake some troubleshooting before filing a support ticket with them. Before you file a support ticket please do the following as it will expedite getting help from Staff. How are you connecting to the internet and to WordPress.com? The way you connect to the internet (mobile, satellite, DSL, dial-up) and to your blog, and how many proxy server jumps etc. it takes to connect can cause problems. There maybe be problems with your ISP and/or with the proxy servers.
Are you using http:// or https:// see http://en.support.wordpress.com/https/
Which browser and version of it are you using? Have your tried clearing your browser cache and cookies? http://en.support.wordpress.com/browser-issues/#clear-your-cache-and-cookies
Is your browser version up to date? You can upgrade any browser version here.
Do you have third party cookies enabled? Do you have another browser you can try?
You can use this link to see if your Flash is up to date. http://www.adobe.com/software/flash/about/ If it’s not up to date then this is where to download and install the latest version of Flash. http://www.adobe.com/products/flashplayer/
Sometimes operating system and/or security system updates can cause problems so check for known issues. When you make adjustments to your browser settings — changing privacy settings, deleting cookies or increasing security — you will need to close your window and restart the browser before those new settings become effective.
Here’s the link to create a support ticket for Staff http://en.support.wordpress.com/contact/ After you use the searchbox, under the search results, at the bottom of the page there will be a section that says “Have you found the answer to your question?” You can choose either “Yes I found the answer to my question.” or “No I didn’t find the answer to my question and I would like to contact support for help.” The no option will reveal the contact form.
If you cannot use that link then email [email redacted] and provide all your details.