nightskyisme

Hi All, new to the forum and need a little help on this machine: Already had 10 cams hooked up and working fine, including on the IRAS software. Installed 4 NEW cams and after plugging them in (and turning them "on" in DVRs settings) I cannot get a picture on the PC (through the IRAS) but DO get a picture on the local (BNC) monitor. Driving me (and the customer) nuts! Why aren't the new cameras showing in the IRAS? The new camera title shows actually, but no image....Anyone??? Thanks