Gap between tiled background textures

Hello. I'm sorry that my first post here is to ask for help but I'm not sure what else to do. This is the first problem I have had in C2 that I have not been able to find a solution for.

The problem I am having involves 2 different tiled backgrounds. They are supposed to align perfectly with one another although I am finding there is a hairline gap created between the two different images. Zooming in (on the layout screen), it looks like the images are blurred around the edges with transparency. The images look completely solid upon inspection so I am unsure as to why this is happening.

I have uploaded a capx file with the problem in it down below. The two backgrounds having the conflict are the horizontal wall and the corner piece. Thanks in advance for any help with the situation.

file - dl.dropbox.com/u/68839782/texturegap.capx

You can use the arrow keys to move across the numbers to zoom in/out

Never mind, I changed the corner pieces from tiled backgrounds to sprites and although the gap still appears in the layout editor upon loading the game in the browser it looks perfect.

If anyone knows the reason why the two tiled backgrounds weren't working together or if the problem corrects itself once exported I'd like to know, but otherwise the problem seems solved. Thanks to anyone who took the time to look at it