ok, so if you are not a coder, this may seem horrible to look at, but forget the nasty yellow symbol in the error box and look at what it says.
broken down, it means something along the lines of:
An object/asset/node etc has not been defined and as such, no filename property can be found as part of it as it does not exist.
The filename property is assigned/checked by the function where the error occurred.
I have not looked at the macro, but am I right in assuming that the code shown is a default/unedited version of the macro script that ships with max?
If so (and I feel I am right), then some further investigation is needed. At face value, it could be that a render to texture node was made, assigned and deleted, leaving an empty node with a filename in the session memory or similar, but lets start with the beginning.
You say you got the app today.
Remind yourself and us of what you did.
Is it the case that you opened the app for the first time and then opened the render to texture and it failed?
OR
Had you been working fine, then tried it and it failed?
OR
Had you installed any plugins from an external source?
OR
Opened an old file from a previous version that may have plugin data no longer available. (This is probably not it but think of anything that you did or may have done to the default install)
Be as factual as you can and then the cause may be easier to define.
Also, have you shut down the app/machine and tried again in a blank scene?
If so, what happened.
