Problems with Import in Contributor using macros

[EP_explorer]

IBM Cognos Planning 8.4
DB - Oracle

I want to load data in Contributor Application using Import Data. When I do it in CAC manually everything is OK. But I have problem in automating this process.

When I launch macros which contains Upload an Import File command it failed and shows in Error Details the message

Unable to execute macro step 'Upload an Import File'
Unable to Bulk Load the data.
Permission denied

Also in log file I found that the Bulk load tried to launch by unknown user with unknown password. May be the reason in it? But what I should do to add user under which bulk load will be launched? Also I can add that Cognos services are launched under the System (not under the any user).

What should I do to tackle the problem?