Same issue with version 1.03. The email was created but the exploit was never triggered, it sat on the blank email screen if left.
I had 1.02 and the previous taihen beta installed offline.
I upgraded to switchkaku 1.03 and installed the offline exploit but had the same issue you list.
Today I:
*pressed select to reset the email app
*tried pressing triangle and start, both gave some errors:
http://i.imgur.com/zNKjHQ9.jpg
*repeated the last 2 steps, same error
*quit switchkaku, opened the email app then closed it
*opened switchkaku and pressed triangle (without first pressing select). It installed successfully
*pressed R to reboot
Offline taihen now loads correctly
I did a bit more testing, repeating the above steps and got the same issue after using select to reset the email app.
A few other things I noticed:
*Sometimes you get 2 'taihen' entries in the email app rather than just one. I thought this was tied to swapping between taihen and henkaku but now I cant recreate it
*If you leave the vita in flight mode and try to install the offline exploit with the triangle/start button, you get the following error which doesn't clearly state that the user is an idiot and wifi isn't on
http://i.imgur.com/zfm3ZAa.jpg
Did you try turning off the wireless in settings before you went into the email app? If you have it installed correctly it'll only launch if wireless functions are off.
I just successfully launched the offline exploit about 10 times with wifi enabled.