<i>…this is what I found. File system error occurred. Error number 3025. Copy command ended because of error. Error 3025 refers to no such path or directory. … That is not the case otherwise I and the other users would get the same message.</i>
A directory can be available to some but not others.
<i>The user in question is defined to the IFS.</i>
I don’t know what that means. Users aren’t ‘defined’ to the IFS. The IFS is the IFS for every user. (However, individual directories may be visible to different users; directories may be ‘mounted’ under some conditions and not others.)
Please provide an example of the CPYFRMIMPF command. Also show any variable values that might be substituted into parameters. This might suggest other questions for more clarification.