The striker was the club's record transfer sale when he joined Peterborough in 2007 and grabbed his 32nd goal of the season for Posh in their 5-0 thrashing of the Daggers on Saturday.
Arber said: "The disappointing thing was it was not a 5-0 game, anyone who saw it will tell you that.
"We missed enough chances to be up at half-time but credit to them as they did a professional job.
"We didn't get relegated at Peterborough though, it was over the whole season and we haven't been quite good enough.
"We struggled for goals. If we had a Craig Mackail-Smith we would be safe but that is the harsh reality of life."
Source: PA
Source: PA