I am able to download the following files from this location:
wget https://cmaq-release-benchmark-data-for-easy-download.s3.amazonaws.com/v5_5/ISAM_Benchmark/POST/combine/scripts/run_combine_ISAM_aconc%2Bdep_example_cb6r5_ae7_aq_12ne3_benchmark.csh
There may be a problem with the + symbol used in the name. Please try visiting the website above, and then using copy of the url and then use wget.