Hi there,
I am wondering if HeadAC3he can convert a mp2 file from 44.1Khz to 48Khz, if so, do I just load up the mp2 (44.1Khz) in the source and uncheck the box of "convert to 44.1"???

Notice the box actually says "Resample to:". Just check that box but select 48 kHz from the drop down menu next to it.

just like PyRoMaNiA post is right but test if the pitch is correct!

I do agree. That looks pretty logical and should work. The reality on my
computer is a little bit different. I can resample only down means from
high to low (48 -> 44.1, 44.1 -> 32, etc.) but as soon as I check box
resample and I'm going from low to high rate (32 -> 44.1, 32 -> 48, 44.1
-> 48) and I hit start button it's unchecked automatic and as a result I'm
not getting resample with higher bitrate. I'm using goldwave to convert
.wav file to higher bitrate and after that I'm converting it to mp2 with
headac3he.

Oh, ok.

I've never actually done it from a lower rate to a higher rate, so I assumed that would work. Thanks for the tip!