Hi @Abid_Rehman,
Can you indicate which specific version of OJS you’re using (e.g. 3.3.0-6)?
You may want to have a look at this post here where a user was able to resolve this issue: Problems with installing and updating plugins on DirectAdmin [SOLVED]
And just an FYI: uploading plugins this way isn’t advisable. The preferred way to add plugins is through the plugin gallery - this ensures that you can check on the correct version of the plugins and that they get installed correctly
-Roger
PKP Team