please help append videos

[goatvideo]

hello, i want to join 2 videos with mkvtoolnix 2.9, but ive come across with this error message

"Appending a track from a file to another track from the same file is not allowed. This is the case for tracks number 4 and 5"

hope you can point me on the right direction here,
dunno whats wrong
and here's the data:

First video: Codec 4CC: H264
Image Size: 1280x544
Aspect Ratio: 1:1 (1:1)
Frame Rate: 23.976 fps
Frame Count: 1036 frames
Total Duration: 00:00:43.209

Second video: Codec 4CC: AVC1
Image Size: 1280x544
Aspect Ratio: 1:1 (1:1)
Frame Rate: 23.976 fps
Frame Count: 362156 frames
Total Duration: 04:11:44.938

thank you v much! :D

[DJ Bobo]

There are identical tracks in both videos. According to mkvtoolnix, they are tracks 4 and 5. Remove one of them.

You better post a screenshot though so that we understand the case better.