html_entity_decode() expects parameter 1 to be string, array given

This indicates there is some unexpected data in your database…in this case, a multidimensional array. Participants Database does not normally store such arrays in the database (it stores only “flat” arrays), so it may be something that was imported directly to the database.

This can be difficult to find because unless you know which record it was that caused the problem, you need to search the database for the value that is giving you this message. A multidimensional array will look something like this:

a:1:{i:0;a:3:{s:4:"name";s:11:"Susan Smith";s:4:"city";s:6:"Boston";s:5:"state";s:2:"MA";}}

There will be flat arrays that will look similar in the database, but a multidimensional array is one that has a “a:” inside the curly brackets. Did I mention it would be hard to find?

Anyway, i’d be interested to hear what you discover about this.

by the way, a multidimensional array is an array of arrays, a flat array is simply an array of values.