Big problems MDL-ERROR

Hello,
I have 2 PBX machines with Sangoma cards:
1st:
1 . AFT-A102-SH : SLOT=4 : BUS=9 : IRQ=17 : CPU=A : PORT=1 : HWEC=64 : V=33 +01:DS26521: PCI: NONE
2 . AFT-A102-SH : SLOT=4 : BUS=9 : IRQ=17 : CPU=A : PORT=2 : HWEC=64 : V=33 +02:DS26521: PCI: NONE
3 . AFT-A102-SH : SLOT=4 : BUS=13 : IRQ=16 : CPU=A : PORT=1 : HWEC=64 : V=33 +01:DS26521: PCIe: PLX1
4 . AFT-A102-SH : SLOT=4 : BUS=13 : IRQ=16 : CPU=A : PORT=2 : HWEC=64 : V=33 +02:DS26521: PCIe: PLX1
Sangoma Card Count: A101-2=2

2nd:
1 . AFT-A102-SH : SLOT=4 : BUS=11 : IRQ=11 : CPU=A : PORT=1 : HWEC=64 : V=33 +01:DS26521: PCIe: PLX1
2 . AFT-A102-SH : SLOT=4 : BUS=11 : IRQ=11 : CPU=A : PORT=2 : HWEC=64 : V=33 +02:DS26521: PCIe: PLX1
Sangoma Card Count: A101-2=1

1st PBX was reinstalled in August this year and second in December. Both have the newest FreePBX distro on board.
Starting from the last week this kind of errors started to appear on both PBX (already about 4 times):

[2013-12-23 09:26:14] ERROR[3393] chan_dahdi.c: PRI Span: 1 TEI=0 MDL-ERROR (J): N® error in state 7(Multi-frame established)
[2013-12-23 13:56:09] ERROR[3393] chan_dahdi.c: PRI Span: 1 Trying to queue MDL-ERROR (F) when MDL-ERROR (F) is already scheduled

People couldn’t call and to fix this it is necessary to reboot the machine.
Our provider claims that this problem is rather on our side, but I don’t know what should I do to investigate what the cause of the problem is. Please help…

I’m having the same issue (I have Digium cards) - need to reboot the machine. Did you ever figure out a resolution? Thanks.