What is the content of "mylist.txt"?

for /f %f in (mylist.txt) do search -name -i *.* -dir D:\Temp\PPM9422 
+%f
[download]

is wrong. That must read

for /f %f in (mylist.txt) do search -name *.* -i -dir D:\Temp\PPM9422 
+%f
[download]

or if you want to search for *.* then you can omit the -name parameter:

for /f %f in (mylist.txt) do search -i -dir D:\Temp\PPM9422 %f
[download]