Apple Script error -10000

Hi, I'm again now i have an other big problem with my script. everything of it works, until the last line I get error msg -10000

here is my script:

tell application "Finder"

set userd to (user domain) as text

set AppSupportPath to (path toapplication supportfromuser domain) as text

set bin to AppSupportPath & "minecraft:bin"

set frage to display dialog "Wollen Sie die Version von Minecraft wechseln?" buttons {"Ja", "Nein"}

if button returned of frage = "Ja" then

if folder "_back" of folder bin exists then

if file "minecraft.jar" of folder bin exists then

duplicate file "minecraft.jar" of folder bin to folder "_back" of folder bin

end if

else

makenewfolderatbinwith properties {name:"_back"}

end if

if file "minecraft.jar" of folder bin exists then

delete file "minecraft.jar" of folder "bin" of folder "minecraft" of folder AppSupportPath

else if folder "minecraft.jar" of folder bin exists then

delete folder "minecraft.jar" of folder "bin" of folder "minecraft" of folder AppSupportPath

end if

set mcversion to choose from list {"Beta 1.1_02", "Beta 1.4_01", "Beta 1.5_01", "Beta 1.9.6", "Vollversion 1.2.5"}

set lol to result

if lol = "Beta 1.1_02" then set lol to folder "versions:Beta:1.1_02" of userd

if lol = "Beta 1.4_01" then set lol to folder "versions:Beta:1.4_01" of userd

if lol = "Beta 1.5_01" then set lol to folder "versions:Beta:1.5_01" of userd

if lol = "Beta 1.9.6" then set lol to folder "versions:Beta:1.9.6" of userd

if lol = "Vollversion 1.2.5" then set lol to folder "versions:Vollversion:1.2.5"

duplicate file "minecraft.jar" of folder lol to folder bin

end if

end tell

error msg:

tell application "Finder"

path toapplication supportfromuser domain

--> alias "Macintosh HD:Users:manuelfederanko:Library:Application Support:"

display dialog "Wollen Sie die Version von Minecraft wechseln?" buttons {"Ja", "Nein"}

--> {button returned:"Ja"}

exists folder "_back" of folder "Macintosh HD:Users:manuelfederanko:Library:Application Support:minecraft:bin"

--> true

exists file "minecraft.jar" of folder "Macintosh HD:Users:manuelfederanko:Library:Application Support:minecraft:bin"

--> false

exists file "minecraft.jar" of folder "Macintosh HD:Users:manuelfederanko:Library:Application Support:minecraft:bin"

--> false

exists folder "minecraft.jar" of folder "Macintosh HD:Users:manuelfederanko:Library:Application Support:minecraft:bin"

--> true

delete folder "minecraft.jar" of folder "bin" of folder "minecraft" of folder "Macintosh HD:Users:manuelfederanko:Library:Application Support:"

--> folder "minecraft 20.21.46.jar" of item ".Trash" of folder "manuelfederanko" of folder "Users" of startup disk

--> error number 0

choose from list {"Beta 1.1_02", "Beta 1.4_01", "Beta 1.5_01", "Beta 1.9.6", "Vollversion 1.2.5"}

--> {"Beta 1.5_01"}

copy file "minecraft.jar" of folder {"Beta 1.5_01"} to folder "Macintosh HD:Users:manuelfederanko:Library:Application Support:minecraft:bin"

--> error number -10000 from folder {"Beta 1.5_01"}

Ergebnis:

error "„Finder“ hat einen Fehler erhalten: Fehler in der AppleEvent-Routine." number -10000 from folder {"Beta 1.5_01"}