What does "ibm_acpi: ec object not found" mean?

[Adam Funk]

According to my logcheck output, every Sunday morning around 07:38 to
07:40 the following message appears in syslog on two Ubuntu machines
with different hardware (one is a Pentium dual-core, the other is an
Athlon single-core):

  kernel: [17516314.136000] ibm_acpi: ec object not found

(The numbers in [] vary.)

What does this mean?  Should I just keep ignoring it?

Thanks,
Adam