This error is normal on the 532. It means you haven't powered up the hydraulics yet.
FYI, you can always see the meaning of an error code on the 532 by pressing the HELP key. HELP doesn't tell you much, but it's better than nothing.
To clear the I01 and start the machine...
Close the front doors on the machine.
Press and hold the CLEAR key, then press the ON button which is just above the red E-Stop on the main console. You should hear the hydraulics start. You might need to hold the ON and CLEAR keys for a couple seconds while the hydraulics come up to pressure.
Then release the ON button and then the CLEAR key. The I01 error should be gone and your hydraulics should be running. But, you should see an I171 error now. Open and then close the doors, and press CLEAR again, and the I171 error should be gone.
If all is well, the machine should be ready for homing (called RP or Reference Position) on the Maho). If you get any other errors, or if the hydraulics don't stay on after releasing the ON button, then you have a different problem.
Sometimes, you might need to press CLEAR and ON for a couple seconds, release them, and then do it again in order to get the hydraulics to stay on.
The next thing you need to do is RP (Home) the axis.
Select "RP Axes Selection" (the F6 key). Press the key for each axes (e.g. X, Y, Z). RP should appear beside each axes designation on the screen.
Make sure the Rapid speed dial is set to 100 (knob in upper left corner on control, near the F1 key).
Press the START button (the green button on the lower right corner). This will cause the X, Y, and Z axis to move into their home position. Make sure nothing will collide. Be ready to hit the E-Stop if there is a collision danger.
Finally, on my machine at least, if you hit any E-Stop on the machine, the I01 error will return, but I have to power down the entire machine before I can get it to power up again with the above procedure. I can't just hit E-Stop, release it, and then re-power the hydraulics without a full power cycle of the main power switch.
P.S. PM me, and I can send you the 532 Operator's Manual and a Constants and Error Codes list for the 532 controller. I don't have any other manuals for your machine, though.