"My action isn't working right" and "my action keeps stopping and asking me to confirm steps" are two complaints that I've often heard from Photoshoppers who've just started to use actions - often that they got from somewhere like Fred Miranda and often accompanied by a plaintive "it never used to be like this".

One possible solution to these problems is understanding the "toggle item on/off" (item toggle) and "toggle dialog on/off" (dialog toggle) options. These can be found on the left-hand side of the Actions palette. Here's a screenshot from my ACR Menus action: 

The item toggle is the left-most column and will show a red or black check mark or be empty. A black check mark against an individual command in an action indicates that the statement will be executed when the action is played; conversely, an empty box means the statement will be ignored. A red check mark will only appear against an action title, for instance, "Sharpness Options" and "Silence Noise". This indicates that there is, at least, one statement that has been toggled off. An empty box against an action title means that all statements are excluded. In other words, nothing will happen when this action is run.

By default, when an action is created all statements are included, so there will be a black check against the individual statements and the action title. To exclude a statement, click on the item toggle box next to the statement. Check again and it will be toggled on. If you check against the action title, then all statements in the actions will be excluded or included depending on the current toggle status.

In my development of ACR Menus and LinearSharpenMenu, I have made use of the item toggle as a menu option selector, however, it is very easy to inadvertently check (or uncheck) an action statement or, even a complete action. In most cases, you can correct a misbehaving action by ensuring that a black check mark appears against the action title.