Thread:Project:Support desk/Problem With File Upload: Could not acquire lock for "mwstore://local-backend/local-public/1/1e"./reply (23)

It's trying to create a directory in the directory specified in the variable. Check what you set in that variable in LocalSettings and be sure it's writable by the webserver.

Try to change permissions recursively for that folder to 777. If that fixes the problem, then you can restrict it further, but be sure to make it owned by the user running the apache.