problems with RT2860 driver since kernel 3.0.0.15

Since update to kernel 3.0.0.x there a continous network disconnects with my RT2860 wireless network interface. The NIC will be reconnected after a few seconds. dmesg reports following errors:

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[ 1050.399007] ===>rt_ioctl_giwscan. 2(2) BSS returned, data->length = 482
[ 1050.399254] /home/the/Treiber/2010_07_16_RT2860_Linux_STA_v2.4.0.0/os/linux/../../common/cmm_asic.c:3387 assert KeyIdx < 4failed
[ 1050.399270] /home/the/Treiber/2010_07_16_RT2860_Linux_STA_v2.4.0.0/os/linux/../../common/cmm_asic.c:3387 assert KeyIdx < 4failed
[ 1050.404538] ==>rt_ioctl_siwfreq::SIOCSIWFREQ[cmd=0x8b04] (Channel=1)
[ 1050.406289] bridge-ra0: disabling the bridge
[ 1050.406403] /home/the/Treiber/2010_07_16_RT2860_Linux_STA_v2.4.0.0/os/linux/../../common/cmm_asic.c:3387 assert KeyIdx < 4failed
[ 1050.406419] /home/the/Treiber/2010_07_16_RT2860_Linux_STA_v2.4.0.0/os/linux/../../common/cmm_asic.c:3387 assert KeyIdx < 4failed
[ 1050.444091] bridge-ra0: down
[ 1050.444109] bridge-ra0: detached
[ 1050.604417] userif-4: sent link down event.
[ 1050.604420] userif-4: sent link up event.
[ 1051.047654] /home/the/Treiber/2010_07_16_RT2860_Linux_STA_v2.4.0.0/os/linux/../../common/cmm_asic.c:3387 assert KeyIdx < 4failed
[ 1051.047672] /home/the/Treiber/2010_07_16_RT2860_Linux_STA_v2.4.0.0/os/linux/../../common/cmm_asic.c:3387 assert KeyIdx < 4failed
[ 1051.549094] /home/the/Treiber/2010_07_16_RT2860_Linux_STA_v2.4.0.0/os/linux/../../common/cmm_asic.c:3387 assert KeyIdx < 4failed
[ 1051.549112] /home/the/Treiber/2010_07_16_RT2860_Linux_STA_v2.4.0.0/os/linux/../../common/cmm_asic.c:3387 assert KeyIdx < 4failed
[ 1051.664159] /dev/vmnet: open called by PID 2350 (vmnet-bridge)
[ 1051.664185] /dev/vmnet: hub 0 does not exist, allocating memory.
[ 1051.664235] /dev/vmnet: port on hub 0 successfully opened
[ 1051.664255] bridge-ra0: device is wireless, enabling SMAC
[ 1051.664263] bridge-ra0: up
[ 1051.664270] bridge-ra0: attached
[ 1051.864061] userif-4: sent link down event.
[ 1051.864070] userif-4: sent link up event.Rcv Wcid(1) AddBAReq
[ 1052.510669] Start Seq = 00000002
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With Kernel < 2.6.38.11 I did not notify such a failure.

Additional info:
I am building ralink driver from source because of issues with default linux drivers.
VMware Player is installed: Version 4.0.1 build-528992

What's going wrong? What can I do?