The last L3E firmware version supported by MS4128-5 hardware is v05.0.11
Extract of v06.0.00 PowerMICE readme:
Attention: The PowerMICE L3E (pmL3E) 06.0.00 software does not support the old
MS4128-5 hardware anymore. This results from the low total memory of this device.
If the software detects this constellation (pmL3E-06.0.00 with MS4128-5) an event
log entry is made (S_watson_UNSUPPORTED_HARDWARE).