You should consider using RaiseError when you connect like ...

my $dbh = DBI->connect("dbi:SQLite:dbname=request_db","","", {RaiseErr
+or => 1});
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Now you will not have to check for errors after every dbi method you call. Your code would then be something like ...

my $dbh;
eval {
   $dbh = DBI->connect("dbi:SQLite:dbname=request_db","","", {RaiseErr
+or => 1});
   $dbh->do($createTableSQL);
};
if ($@) {
   # handle error here
   # the error will be in the $@ variable
   # the error raised could be from the connect or the do methods
}
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Note that I change your prepare/execute/finish to just a do.
This is more concise way of executing DDL statements.