Personal Safes do not open any more after Version-Update

I am currently using Minecraft 1.6.4 (client version) with the following mods:
forge-1.6.4-9.11.1.953-installer
industrialcraft-2-2.0.369-experimental.jar
buildcraft-A-1.6.4-4.2.2.jar
[1.6.4][code=c][forge]LumberJack

now I've tried to update to Minecraft 1.7.2 (client version) with the
following mods:
forge-1.7.2-10.12.2.1147-installer
industrialcraft-2-2.1.483-experimental
buildcraft-6.0.16
[1.7.2]bspkrsCore-universal-6.11
[1.7.2]Treecapitator-universal-2.0.3.jar

The game starts without issues, but then I've imported my map from the previous version and now I am no longer able to open all personal safes I created. I am getting a post, that "this safe belongs to ..." and gives my players name. I am still using the same account (in fact I only have this one)
Then I've tried to remove all personal safes in my previous version, imported this map again to the new version and installed one personal safe. I was able to open it once, but then again the same happened and I couldn't open it any more.

Can anyone help me on getting the safes to open again?

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Windows 7 Ultimate 64bit
Sun Java 1.7.0_17 64bit

It's the client-game, not server. There is no OP in client-games as far as I know. If there is a OP can you tell me how to check and maybe change this?

found some time to test the above:
when opening the game to LAN, i am able to open the chests again, but when leaving the LAN-mode, I am not able again. Also I've tried setting up the game without a dos-batchfile (which I used to redirect the %appdata% variable.
the tipp about the changed player-id sounds legit to me. Any idea how to update my map?

i did similar: i emtied them in my older version, then broke them, imported the map and put one safe. I was able to access it once, but then again the same problem

Is there anything to OP my player in singleplayer-mode?!

nope, didn't help

ok did another test - maybe this will sort it out: i created a new world in 1.7.2 and set a personal safe. Again, I was only able to access it once, then the error happened ... maybe there is some kind of a bug. I'll try out the newer version now

ok, tried it with Minecraft 1.7.10 and industrialcraft-2-2.2.499-experimental and finally it worked. But as buildcraft is not yet available for 1.7.10 i'll have to wait for this release.

Thanks to all for your help.

Quote from Kye_Duo

why are you using personal safes in SP anyway?
for the explosion protection? if so, go pickup Iron chest mod, you'll get a chest with 108 slots that is Nuke proof.

No it's because of double the capacity of a normal chest and they can be put directly sidebyside and one above the other.