error 6 while trying to use set_perm in updater-script

Heloo, i have hard times finding a solution to my problem, here my script :

Code:

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ui_print("Starting...");

mount("ext4", "EMMC", "/dev/block/mmcblk0p41", "/system");
ui_print("...system mounted");

package_extract_dir("modifiedframework", "/system/framework");
ui_print("...framework-res.apk transfered");

set_perm(0, 0, 0644, "/system/framework/framework-res.apk");
ui_print("...permissions set");

unmount("/system");
ui_print("...system unmounted");

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it return : Updater process ended with ERROR: 6

and the script is working fine if i remove the line

Code:

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set_perm(0, 0, 0644, "/system/framework/framework-res.apk");

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any help is welcome, thanks you

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