acpi error: battery not found

Binary package hint: acpi

ubuntu 9.04 32bit
acpi Version: 1.2-1ubuntu1
kernel: 2.6.29.4

Jun 8 16:24:08 omg kernel: [25831.049587] ACPI Error (dswload-0790): [_T_0] Namespace lookup failure, AE_ALREADY_EXISTS
Jun 8 16:24:08 omg kernel: [25831.049602] ACPI Exception (psloop-0227): AE_ALREADY_EXISTS, During name lookup/catalog [20081204]
Jun 8 16:24:08 omg kernel: [25831.049614] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.BAT1.UBIF] (Node f7414648), AE_ALREADY_EXISTS
Jun 8 16:24:08 omg kernel: [25831.049632] ACPI: Marking method UBIF as Serialized because of AE_ALREADY_EXISTS error
Jun 8 16:24:08 omg kernel: [25831.049723] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.BAT1._BIF] (Node f7414618), AE_ALREADY_EXISTS
Jun 8 16:24:08 omg kernel: [25831.049739] ACPI: Marking method _BIF as Serialized because of AE_ALREADY_EXISTS error
Jun 8 16:24:08 omg kernel: [25831.049835] ACPI Exception (battery-0352): AE_ALREADY_EXISTS, Evaluating _BIF [20081204]
Jun 8 16:24:08 omg kernel: [25831.054551] ACPI Error (psargs-0359): [_T_0] Namespace lookup failure, AE_NOT_FOUND
Jun 8 16:24:08 omg kernel: [25831.054566] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.BAT1.UBIF] (Node f7414648), AE_NOT_FOUND
Jun 8 16:24:08 omg kernel: [25831.054666] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.LPCB.EC0_._Q09] (Node f7419270), AE_NOT_FOUND