There are three things that I noticed and maybe they could make a difference:

• selectcol_arrayref and selectall_arrayref return an array reference. You are assigning their return value to an array
• After you assign to @row the value of a fetch, you assign something else, without using that result. Moreover, your second "my @row" declaration will hide the first one. If you use warnings, it will tell you straight away.
• You are using "select max(word_id)" to get a count. This will work as long as you don't delete any record in your table. You should use "COUNT(*)" instead.

I don't know if these items are responsible for what you are complaining about, but surely they look suspicious.

HTH