Michelle,
My guess is that the issue you're running into is data specific, although I'm not ruling out other possibilities. I would focus your attack on the feature class for which you're trying to utilize the Find functionality.
1. Does the issue happen on all feature classes or just a single feature class?
2. If you check only this feature class out to axf and consume it in ArcPad does it still lock up?
3. If you create a new feature class with one field, add a few new points in ArcPad and give them some attributes, check out to axf and consume in ArcPad, does the Find functionality work?
If you find that it's just one feature class that's causing the issue, I would try creating a new feature class with identical schema and loading the existing data into it via ArcCatalog. Does the issue still occur?