StringRegExp: extract Date from Pathname

Hi everybody,
 
I'd like to extract the Date (Folder Name) from a path that is saved as Local Constant:

Local $Date=0
Local Const $metaPath= @ScriptDir & "\warra\2015\150128\procEagle\rad\EA_warra_test.meta"
;Local Const $Date= "20" & StringRegExp($metaPath, '([:digit:]{6})', 1)
$Date= StringRegExp($metaPath, '(?:\)(\d{6})(?:\)', 0)

I want to get the 150128, to send it  to a text file later

Send("Time:{ENTER}Date{TAB}" & $Date & "^s")

But no matter what I try, I get no matches (output '0' or nothing at all). Other operations are able to work with $metaPath.

Where is my error?
 
Thanks for replies.