I recorded a video: http://videobam.com/jtRrB
The lcd constructors which makes the LCD blink 3 times but without characters on it are:
1) lcd ( 0x20, 4, 5, 6, 0, 1, 2, 3, 7, NEGATIVE)
2) lcd ( 0x20, 6, 5, 4, 0, 1, 2, 3, 7, NEGATIVE)
3) lcd ( 0x20, 6, 5, 4 0, 1, 2, 3, 7, POSITIVE)
4) lcd ( 0x20, 4, 5, 6, 0, 1, 2, 3, 7, POSITIVE)
2 of the 6 lcd constructors from guesser skectch only make on the backlight but without blinking.
P.S. And I soldered the pins one more time.

The I2C circuit now makes contact with the LCD for sure.