Timeshift in Behold TV application works only when installed either InterVideo MPEG codec or codec built-in to OS Windows 7 Home Premium or higher. InterVideo codec is installed to system with installation of InterVideo WinDVD Creator program from tuner package. You may check the presence of installed MPEG codec in "Timeshift" tab in Behold TV application setting in box "Timeshift ready status".
Also timeshift can not start because of version conflict of different versions from, for example, codec packs. Timeshift ready status can't detect such conflicts. In this case may help codec packs deletion and reinstallation of InterVideo WinDVD Creator application.