Translation:Humans cannot drink Klingon tea. It's too toxic.
That's an acceptable pronunciation of the r in that location. The r shouldn't really have full roll anyway. It was described as being a "light roll" and Dr. Okrand does a single tap/flap when he speaks Klingon. He probably meant the "light" to indicate that it should be a single tap/flap, but Klingonists have come to accept both the single tap/flap and the full roll as legitimate variations.
Similarly the ""rgh*" combination includes a third variation. Dr. Okrand has explained that the r in that combination should, indeed, match the r used elsewhere in Klingon, but does, himself, use an American-style rhotic "r" consistently in the rgh combination. So all three pronunciations of the r are accepted in that combination.