- What is it?: Science fiction episode or short film.
- Tell us what it isn't: It is not The Outer Limits - The Galaxy Being (though the plot is similar).
- What is the plot?: The (marooned) protagonist (male) discovers a recorded message (with visuals) from an alien that explains the creature means no harm, but 'dressed-up' brightly to welcome visitors. Unfortunately the alien's anti-radiation suits leaks and the alien does not survive. The protagonist uses the (patched?) anti-radiation suit to establish contact with the creature and manages to explain the situation. The creature is saddened/ashamed and disappears to avoid further harm.
- When did you see it?: Early 90s on Dutch TV.
- How old was it?: Unsure, probably 80s/90s.
- What language was it?: English.
- Was it part of a series?: Most likely.
- What details can I recall?: The majority of the action takes place in a barren desert-like environment, with the creature dwelling at a cave entrance. There is a 'safe' area where the protagonist watches the recorded message (maybe the spaceship of the alien captain). It could be the protagonist is not alone, but he is the only one confronting the creature. The creature has no clear discernible shape, but has very bright rays of light coming from it.
- Other details: The dialog between the protagonist and the creature contains something like "[the bright 'dress']... causes this death, which you fear?". The protagonist could be a marooned captain of a spaceship, as is the alien that recorded the message.
Yes, I'm quite certain this is the episode The Immunity Syndrome from Space 1999.
Most of the points you mention equate with the plot.
Commander Koenig and company find what appears to be a habitable planet; but it is ruled by a single being who, in its efforts to make contact with the Alphans, unwittingly puts them in peril of their lives!
The quote you mention appears here;