First you will need to have FExplorer on both the phones and then proceed with the steps below
Sender = The person sending thethemefrom his phone
Recipient = The person receiving the theme on his phone
Also I am assuming the theme is saved in the MMC of the sender's phone.
Sender's Steps :
1. Open FExplorer on the sender's phone.
2. Browse to E:\System\skins
3. You will see alot of gibberishly named folder.
4. When you enter into any of those folders, you will see somefiles with the name of the theme.
5. Lets say you want to transfer the theme whose folder is named as 082df835462c1b4a.
6. Send all the content inside the folder 082df835462c1b4a via bluetooth to the recipient's phone.
7. Recipient must make a note of the folder name 082df835462c1b4a 8. The sender's task is over now
Recipient's Steps :
1. Open FExplorer.
2. Browse to E:\System\skins and make anewdirectory/folder named exactly as the folder in the sender's phone. (i.e. 082df835462c1b4a)
3. Go back to the main menu and scroll down to "inbox" and enter it.
4. In the "inbox" you will find the files that the sender sent you.
5. Copy/cut them one by one and paste them in the folder you just made.
6. Exit FExplorer.
7. Go to Themes >> (Move the joystick right to enterthemessaved in MMC) and you will find the new theme there.