Flex compiler – application descriptor: invalid application identifier

Whenever your Flex compiler prompts
“application descriptor: invalid application identifier“,
you might check your application description XML file. Your application ID might contain underscores (in my case) or other invalid characters. Since I found a hint to the solution only at koali.com.au, I think it’s a good idea to reblog it.

Quote from Adobe livedocs:

id – An identifier string unique to the application, known as the application ID. The attribute value is restricted to the following characters:

• 0-9
• a-z
• A-Z
• . (dot)
• – (hyphen)

The value must contain between 1 to 212 characters. This element is required.

The id string typically uses a dot-separated hierarchy, in alignment with a reversed DNS domain address, a Java package or class name, or an OS X Universal Type Identifier. The DNS-like form is not enforced, and AIR does not create any association between the name and actual DNS domains.

More informations about the descriptor file:
http://livedocs.adobe.com/flex/3/html/help.html?content=dg_part_4_1.html