Charlton chief executive Peter Varney has pleaded with the club's fans to back manager Les Reed after he was booed during the 1-0 defeat to Wycombe.
Charlton have won just once under Reed
Around 50 or so supporters continued their vocal protests outside The Valley following the Carling Cup humiliation.
Varney said: "We fully understand the frustration of the fans - but we are urging them to keep giving the management team their support.
"There will be funds made available in the January transfer window," he added.
The Charlton chief also vented his frustration at the Charlton players' performance.
"I'm very surprised that professional footballers, players who had the chance of reaching a major cup semi-final, could not respond against a team that plays two leagues lower than them."
Earlier on Wednesday Scottish club Hibernian rejected a £3m bid from Charlton for midfielders Kevin Thomson and Scott Brown.
Hibs chairman Rod Petrie told the club's website he had rejected the offer because the pair had an important role to play at Easter Road this season.