Ok well, i have seen lots of ppl having probs with this, so here is my guide
Step 1:
Uninstall your Ecsro client and do a clean reinstall
Step 2:
Copy your media.pk2 in to your Ecsro folder (including any other files)
Step 3: (only for error code 5)
before running Ecsro make sure you add it as an exception in your anti-virus.
eg. AVG>Tools>Advanced Options>Exceptions
If it doesn't fix error code 5, disable your anti-virus before your reinstall. then once installed turn it back on and then add the exception. don't start Ecsro before this.
*EDIT* May have screwed up the Numbers... best bet do all 3 for both codes, it'll still work haha!
This is a very general guide. so if it doesn't help, i'm really sorry. I can try to answer questions