kies, ties, etc. - the possessives that don't have -a
kia, tia, etc. - doesn't mean possessive
de = not an adverb
sentema = doesn't mean "sen"
dan─Łero = doesn't mean "ero"
papero = doesn't mean "ero"
procento (use "elcento" instead!!) = doesn't mean "pro cent"

Islando = no one says "isano"
Nederlando = no one says "Nederano"

If you use the nonstandard(?? anyway, shouldn't be allowed) words like "-io" to mean "country" instead of "lando" or "nacio" etc, then there are more problems, for example:

glacio = doesn't mean "ice country".