R.R.
Drop-side cribs are now banned in the US because of deaths associated with a part breaking on the crib, causing an unsafe situation for the baby, and can no longer be manufactured, sold, or re-sold. New standards regarding cribs go into effect June 28, 2011.
http://www.webmd.com/parenting/news/20101215/drop-side-cr...
http://search.cpsc.gov/query.html?col=pubweb&charset=...
http://www.cpsc.gov/CPSCPUB/PREREL/prhtml11/11074.html
Your crib may have been recalled, check to find out. If you know the manufacturer contact them.
16 months may be too young for a toddler bed, hopefully your crib can be fixed and stabilized.