Solving Certificate Error problems

Some of you may have experienced the certificate error when installing a theme on your phone. Now there is a solution for it!We can do with the unsis software. Unsis is quote " a tool to extract and examine the contents of SIS files". With this file you can also use any .sis theme for you symbian phone!
I tried to unsis the Raindrops by Evanfall which was not suitable for my phone (5800XM) so that now I can install it on my Nokia 5800.
See the screenshot below!





Download the unsis software here
then do the following steps

You'll need the usb cable for connecting phone to pc

1. Install unsis to your PC and open it
2. choose "Open SIS" on bottom left
3. choose the theme you want to reinstall
4. click on "Extract"
5. after a few seconds (sometimes more ) it'll be "Completed"
6. you can now close the program
7. go into the PC installation folder (usually C:/Unsis)
8. there should be a folder called "Temp"
9. inside you should find "private"-> "10207114"-> "import"-> "some folders (just one ifyou extracted just one theme) with different names (numbers and letters in most cases)"
10. go inside the folders and search for the one of the theme you are interested in, there'll be 4 files:
a ) NameOfTheFolder.ini
b ) NameOfTheTheme.mbm
c ) NameOfTheTheme.mif
d ) NameOfTheTheme.skn
11. ok? now, leave this folder open and connect phone to pc using the usb cable
12. choose "Mass storage" option. Note: you can also insert memory card into a memory card reader
13. in your phone, find the folder called "private" . If you don't see it, you need to choose the visualization of hidden files and folders
14. in the "private" folder, find "10207114" folder and then "import" folder
15. in "import" there are your themes, here you should find the themes you installed into the memory card
16. don't close this folder but come back to the folder where you extracted the theme with unsis
17. just click "back" so you can see your folder selected into the "import" folder
18. choose all the folder and select "copy"
19. go back to the "import" folder in the phone's memory card
20. right click and "paste" into the "import" folder
21. here we are, now your theme is again in the memory card
22. just restart the phone and check that the theme is in the themes menu list, if it isn't, you'll need to repeat the recovery process.
(thx to Wing Wizard from dailymobile.se)