This error occurs if you install the 05_asl_scanner.conf file and/or the 99_asl_scanner.conf ruleset. These rulesets are not supported without ASL, as malware scanning is not included in the rules only subscription. ASL comes with malware upload scanning for HTTP, SSH, FTP and other protocols, including real time malware protection and much more. If you want malware upload protection, upgrade to ASL.
Option 1. Update to ASL
Option 2: disable this setting in /etc/asl/config
Option 3. Remove the file 05_asl_scanner.conf and/or 99_asl_scanner.conf and restart apache.
This means someone or something has disabled the malware protection system on your system. ASL can not and will not do this.