chemeq: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/chemeq - from package: chemeq
/var/lib/wims/public_html/bin/chemeq - from package: wims

You may install the required package with command apt-get install {package}
Error in other languages:
chemeq: bevel nie gevind nie
chemeq: comandă negăsită
chemeq: comando não encontrado
chemeq: commande introuvable
chemeq: command not found
chemeq: käsku ei ole
chemeq: không tìm thấy lệnh
chemeq: komanda nerasta
chemeq: Kommando nicht gefunden.
chemeq: kommandot finns inte
chemeq: komut yok
chemeq: nie znaleziono polecenia
chemeq: níor aimsíodh an t-ordú
chemeq: no se encontró la orden
chemeq: no s'ha trobat l'ordre
chemeq: opdracht niet gevonden
chemeq: parancs nem található
chemeq: perintah tidak ditemukan
chemeq: príkaz nenájdený
chemeq: příkaz nenalezen
chemeq: команда не найдена
chemeq: командата не е открита
chemeq: 命令找不到
chemeq: コマンドが見つかりません