TypeError: not all arguments converted during string formatting

[Anto007]

Now I get this below new error (I'm using python version 3.6.2; is the error related to it?):
(virtualenv3) user@XXXXX:~/tools/fix_assembly_errors/ctbRA$ ./ra2.py -i contigs.fasta -1 read_1.fastq.gz -2 read_2.fastq.gz
Building a SMALL index
Traceback (most recent call last):
File "./ra2.py", line 1119, in
window = window)
File "./ra2.py", line 975, in curate_assembly
allow_orphan = False, allow_orphan_ends = False, save_mapping = save_mapping)
File "./ra2.py", line 915, in check_assembly
mapping, pr_split = map_reads(assembly, scaffolds, pr, threads, multiple, pr_split = pr_split)
File "./ra2.py", line 86, in map_reads
return run_bowtie(assembly, sam, pr, pr_split, sr, threads, multiple, bt_dir) # run bowtie, return sam file
File "./ra2.py", line 66, in run_bowtie
% (matches_command, threads, bt_dir, assembly.rsplit('/', 1)[-1], pr_command, sr_command, sam)
TypeError: not all arguments converted during string formatting

Originally posted by @Anto007 in #3 (comment)