Wanderers twice hit the bar in the first five minutes while Paul Robinson also saved well from Matt Jarvis.
But the club`s inability to shut out the opposition, with Wolves yet to keep a clean sheet this term, again proved their downfall as David Dunn, Brett Emerton and Ryan Nelson found the net for Rovers.
McCarthy said: "We defended badly. Bearing in mind we haven't had a clean sheet for so long, maybe it's not a surprise.
"We had a bit of bad luck at the start by not scoring but then let's have an ugly point at 0-0, not concede goals that we shouldn't concede.
"We started the game really well. We've just got to keep going and keep working at it."
Source: PA
Source: PA