If two people discussed possibly having a partnership and the one person came to work, was paid a salary and bonus for obtaining business, nothing in writing except for a letter stating that person was a paid employee, but then there was a blow up, is this considered a valid verbal agreement?

Verbal agreements can be binding as long as they are beneficial to both parties. Depends on the dollar amount to a certain extent and also which Court.

Verbal agreements have to be proven though, by evidence to support them.