mrSingh
I'm not getting any error - works fine for me.
I've also unpacked the .capx to check if there are any other non-standard effects in the project but as you can see from the attached, there is only the one non-standard and 2 standard effects.
There is no reference to "black to alpha yann gragino".
<used-effects>
<effect author="Paulo Ricardo Reinehr" id="prralphathreshold">Alpha Threshold</effect>
<effect author="Scirra" id="blurvertical">Blur Vertical</effect>
<effect author="Scirra" id="inverse">Inverse</effect>
<effect author="Scirra" id="blurhorizontal">Blur Horizontal</effect>
</used-effects>[/code:16xw0pq7]
What version of C2 are you using?
What is your OS?
What browser are you testing on?
Can you upload a link to the .capx? (you can bypass posting URL restriction by inserting a couple of spaces within the start of the URL).
This will be quickest way to see what the problem is.