I have an unbranded Ice Cream Sandwich phone. Is it normal that I am unable to store anything on the unit without an SD card inserted? Is that a characteristic of the OS?

To be more precise, I managed to download a few apps. Some others (e.g. Roboform, Maps With Me) simply refuse to work without an SD card inserted. The built-in file manager (ES File Explorer) does not show any files or folders outside of the SD card. Impossible to download / transfer any file into the unit without an SD card.