@ObiWanKenxbi As far as I can tell [coll] can not read text files and even if it could it needs the first argument as a float, the colon with no space before it makes that first float into a symbol. But we can do this with [text], we just construct the symbol in a message but if your first float is always ordered with no gaps we can skip making the symbol as I do in the right hand example. Browse the helpfile for [text], it should do anything you need.
reader.pd
Edit: I guess [coll] can read files, did not look close enough, using absolute instead of relative paths may fix your issue with it not finding the file but you would still have the problem of the first entry actually being a symbol and not a float so to use [coll] you would have to get rid of those colons.