I reported $5,100 for a 1099-misc. Turbo Tax used Form C-EZ...shouldn't it have been Form C? Thank you!

No, Form C-EZ is fine. It's just a simplified Schedule C form. 

Schedule C-EZ, Net Profit from Business is a simplified version of Schedule C that you can use if had only one business (sole proprietorship, qualified joint venture, or statutory employee) and the business:

• Uses the cash method;
• Has expenses of $5,000 or less;
• Doesn't have a net loss;
• Doesn't carry inventory;
• Doesn't have employees;
• Isn't required to file Form 4562 for amortization and depreciation;
• Doesn't have home office expenses; and
• Doesn't have prior-year unallowed passive activity losses. 
  
  (All of the above conditions must be met.)

TurboTax will file the correct schedule based on your business information, but sometimes it generates Schedule C even though your business meets all the conditions for a Schedule C-EZ. This is nothing to worry about – your calculations end up the same regardless.