cultus

Hey guys, so i bought game from steam store(armaII:CO), downloaded first part (usual arma) and i tried to start it and got error sayin :" Data file too short 'addons\characters2.pbo'. Expected 853343647 , got 707788800 B ". Please help me i dunno what to do...i will proceed to download operation arrowhead but it will be bad if this problem continiues. CHEERS