Well.......the problem you are facing...could be because of the upload File-Size limit set by Hamara Forums. The limit is 10 MB. So, In case you have files above 10 MB to be uploaded, you can use WINRAR to 'split' the file into multiple parts, and upload all the parts.
PS: I suggest that even if the file is exactly of 10 MB or very close to the 10 MB mark, better to be on the 'safe' side, and split it into 2 or more parts using WINRAR, and then upload. If you are having any doubts on splitting the file using WINRAR, Check out this link (From Post No.13 onwards) :
http://www.hamaraforums.com/index.php?showtopic=10546#And for any further queries, do post your doubts here....Hope the info was useful enough to you......