Is there any penalty for reviving a dead party member?
Characters revive with stats set to very low values, take them to a Guild (any one, doesn't matter) and use 'Restore' to get their stats back. A Cleric's Rejuvenate spell works too.
Once they've died 15 times they'll start complaining, if they die and revive again they'll leave forever. You can reset the death count at the Alarian altar in the Larvin catacombs.
Cursor keys are not working. Any tips?
Try numlock on/off. The number pad should let you move, F1-F7 select party members, regular number keys 1-8 select the menu options on the right panel, and Return goes back to the previous menu.
I've had issues where it stops reading the keyboard if my screen shuts off due to inactivity, and I have to restart it.
Which attribute is more important?
Definitely strength. You need some strength to move objects and flip certain levers in the dungeon, and you need 50 to rescue the mage from the pit outside town but you can use buffs to reach that. Stat boosts in the first town are inferior to the rest of the game, you can get 2 or 3 points per training slot later on. So its worth it to save your training slots until later (there is a guild in the first town that gives +3 skill though, which is the best place to train it).
Str - damage, certain quests
Stamina - HP regen I believe, kinda pointless
Int - Needed for demon summoning, lets you get more charges out of items. Doesn't increase spell damage or anything like that.
Wis - Mana regen. Useful up to a point
Dex - Turn order and dodging. Very important
Skill - Turn order and accuracy. Also important
Cha - Affects dialogue success and Nymph powers. Mostly unneeded.
Magic power - Needed to overcome magic resistance. Very important for mages.