fix ffmpeg path

tools/pve/post-pbs-install.sh

@@ -65,6 +65,14 @@ component_exists_in_sources() {
   grep -h -E "^[^#]*Components:[^#]*\b${component}\b" /etc/apt/sources.list.d/*.sources 2>/dev/null | grep -q .
 }
 
+require_whiptail() {
+  if ! command -v whiptail >/dev/null 2>&1; then
+    msg_error "Missing dependency: whiptail"
+    echo -e "Install it first (e.g. apt update && apt install -y whiptail), then re-run this script."
+    exit 127
+  fi
+}
+
 # ---- main ----
 main() {
   header_info
@@ -90,8 +98,14 @@ main() {
   CODENAME="$(get_pbs_codename)"
 
   case "$CODENAME" in
-  bookworm) start_routines_3 ;;
-  trixie) start_routines_4 ;;
+  bookworm)
+    require_whiptail
+    start_routines_3
+    ;;
+  trixie)
+    require_whiptail
+    start_routines_4
+    ;;
   *)
     msg_error "Unsupported Debian codename: $CODENAME"
     echo -e "Supported: bookworm (PBS 3.x) and trixie (PBS 4.x)"