This kind of error message so early after starting Paradox usually relates FILES= in the config.sys of the PC running Paradox. This has to be aleast 40.
If FILES=40 (or more to a max of 255, but suggest less than max), it could be that the Paradox NetFile Location has not been set for a networked version of Paradox, but we won't go there yet. I'm sure this has been discussed earlier in this forum.
Phil