Constant string with quote throw Missing closing quotation mark in Atelier

if $e(chunk,1,1)=$c(34)

That's because it's not valid COS syntax :) You need """"

I originally posted this to the Google groups cross post and was informed that it would not be seen unless posted here.

Try
if $e(chunk,1,1)=""""{
}

A double quote character is represented by two double quote characters when inside a quoted segment. So:

write """  ; is invalid
write """"  ; produces
"

As second argument defaults to 1 and third can be skipped you can write just:

if $e(chunk)=""""{
}