The template you have chosen is invalid or cannot be found

I received the error “The template you have chosen is invalid or cannot be found” when trying to create a new site from a custom site template.

Normally when this error occurs it is due to a dependent feature that has not been installed.
I came across this nifty tool, STP Inspector, that shows dependencies for a STP file on the site features and site collection features.

Run the tool, identify the missing features and install them.
Problem sorted.

SharePoint 2010 Feature Manager

For those of you who are familiar with or have used SharePoint 2007 Feature Manager, this tool will come in handy.
SharePoint 2010 Feature Manager is based on the SharePoint 2007 Feature Manager.

It allows you to activate, deactivate, install and uninstall features easily.

Check it out at http://spfm2010.codeplex.com/

Capture task ID for approval task in SharePoint Designer 2010

Assigning the task ID to a field in the current item:

You can access the Task ID from the within the task behaviour. Click on "Change the behaviour of a single task"

The best place to set the field in the list / library would probably be in the "Before a Task is Assigned" "When a Task is Pending". You can add a "Set field in current item" action or if you wish to assign it to a workflow variable you can use the "Set Workflow Variable" action.