Bash Script: Redirecting to file gives “Illegal Instruction”

Question

I'm trying to use a bash script for a study assignment. As a bash noob, I tried to adapt an existing one to suit my purpose: Compile/Make a C-program with different compile arguments, execute it and redirect its output to a file.

The script is as follows:

#!/bin/bash
EXECUTABLE=./PartitionedHashJoin
OUTFILE=results.txt
for sizelog2 in $(seq 0 20)
do
        for buckets in $(seq 2 2048)
        do
                size=$((1<<$sizelog2))
                make clean
                make PartitionedHashJoin NUM_RELATION_R=$sizelog2 NUM_BUCKETS=$buckets
                echo -n $sizelog2 " " $buckets " " >> $OUTFILE
                $EXECUTABLE >> $OUTFILE
        done
done

However, bash throws an error:

...: line 6: 11927 Illegal instruction: 4 $EXECUTABLE >> $OUTFILE

If I remove the redirecting of the executable's output, then it works.

I do not get what I could have typed wrong in the redirection - it works just fine in another example with just one loop. Google didn't have a suggestion so far for what I'm doing wrong.

Can anyone spot it?