There were some very minor problems in the original package with cookies in the PHP scripting where Dingetje had left it configured with his own URL on accident. These corrections were posted to solve those problems and the package was re-packaged under the "a" version with these corrections already included. It was also updated to be compliant with the newer versions of FREESCO so that the rc_httpd file was not placed in the ramdisk and lost after a reboot in 036+ systems. So I would recommend installing the "a" version.
If you are afraid that you might make a mistake. The chances are high that you will never learn anything.