Yeah, unfortunately you need to carefully examine frogs sold in pet stores to make sure they aren't already displaying symptoms of being weak and sick. Sorry for your loss. Dude 100 watt bulb is way too intense for a 10 gallon; 45-50 watt is plenty for a 10 gallon. Just buy a spray bottle and fill it with dechlorinated water to spray the sides and dirt for getting to the humidity level required for these guys.

Achieving high humidity by just leaving a water bowl set in there isn't going to get a lot of moisture in the air. That's cool you picked up a new one and is healthy; hopefully you have a better experience with this one. Since these guys don't require large water bowls, it's not necessary. Most importantly is to buy one that is shallow or fill enough water to where it sits right under their throat. You can buy a large bowl, just make sure it's shallow.