If a specific post was interesting or useful to you, we recommend that you Like that post. It tells the post author, and others, that you found the information valuable. Clicking Like is another way to let others know that you enjoy it without leaving a comment.
Log in to join the conversation and Like this content.
I'd check your web logs to see if a security module on the server is causing the error; the UBB.threads Test Script will let you know if your host is using Suhosin or another problematic security module.