Insert array into PDO (PHP): "SQLSTATE[HY093]: Invalid parameter number" - php

Question

Inserting an array via PDO into a MySQL-Database with PHP doesn't work for me. It says "invalid parameter number", even though the array has 41 values; the PDO names 41 columns; and the prepared query has 41 question marks.
The array has 41 values (I checked with var_dump), like this:
$data = [
'countrycode' => $_GET["id"],
'country' => $_GET["country"],
'region' => $_GET["region"],
'law_db_region' => $_GET["law_db_region"],
[... etc ...]
]
My PDO code is the following (yep, these are 41 columns & 41 question marks):
$sql = "INSERT INTO awards_country
(countrycode, country, region, law_db_region, law_db_national,
law_db_national2, const_url, const_version, const_date, const_dummy,
const_article, const_wording, const_article2, const_wording2, const_article3,
const_wording3, law_dummy, law_act, law_article, law_source,
law_date, law_act2, law_article2, law_source2, law_date2,
law_act3, law_article3, law_source3, law_date3, web_dummy,
web_url, web_organ, web_language, web_date, web_url2,
web_organ2, web_language2, web_date2, wikipedia_url, wikipedia_date,
comment)
VALUES (
?, ?, ?, ?, ?, ?, ?, ?, ?, ?,
?, ?, ?, ?, ?, ?, ?, ?, ?, ?,
?, ?, ?, ?, ?, ?, ?, ?, ?, ?,
?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?
)";
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$stmt = $conn->prepare($sql);
$stmt->execute($data);
The error I get is nevertheless:
Fatal error: Uncaught PDOException: SQLSTATE[HY093]: Invalid parameter
number: parameter was not defined in [...]country-insert.php:99
Stack trace: #0 [...]country-insert.php(99):
PDOStatement->execute(Array) #1 {main} thrown in
/data/web/e96483/html/awards/country-insert.php on line 99

Answer 1

Not the answer, but a recommendation (and to large for a comment).
Extracted from your code and reformatted for clearness:
const_article, const_wording,
const_article2, const_wording2,
const_article3, const_wording3,
...
law_act, law_article, law_source, law_date,
law_act2, law_article2, law_source2, law_date2,
law_act3, law_article3, law_source3, law_date3,
It seems, that this is a 1:N relation. And you are working with relational database system (mysql). So why not use relations and one or more additional tables?
In fact, not using relations here will make other (future) request much more complicated.

Answer 2

for ? param you should not use an associative array but pass values as a positional
$data = [
$_GET["id"],
$_GET["country"],
$_GET["region"],
$_GET["law_db_region"],
[... etc ...]
]