cssmerge: 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 CentOS possible default full paths are:

/usr/bin/cssmerge - from package: crm114

You may install the required package with command yum install {package}

On Debian possible default full paths are:

/usr/bin/cssmerge - from package: crm114

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