noob here

[b8vr]

Be aware that -d and -D are two different things. Also, in the last message you use -a7. That is a hybrid attack where you need to supply a mask followed by a wordlist. There's no mask in your command.
An example of that is

Code:

hashcat.exe -m 12500 -a 7 -w 3 -O -o crackedserdar.txt $RAR3$*0*e43478c3e9a378f4*38bc0fe86c6decbd5b0d011b87c3e289 ?l?l?l example.dict

That would create 3 lowercase chars in front of each password candidate in the wordlist.