I've been using this MPE installation since 1.7 was released without this error.
I think it happend when I ran up of disk space on my C: drive, but I'm not absolutly sure.
I also see that the SMS.dat is created, but its size is 0 bytes.
NOTE: Removing the file solved the problem with the error message. But the bug remains. This shouldn't happen.
Here is the error log
=============
10:15:33.57 DataLen=27379 Response=OK True
10:15:33.57 SMS Daten empfangen...
10:15:33.57 Import SMS, 282 Zeilen...
10:15:33.81 SMS dekodiert, MultiSMS werden berechnet...
10:15:33.81 MultiSMS (Inbox) berechnet
10:15:33.81 MultiSMS (Drafts) berechnet
10:15:33.81 MultiSMS (Sent) berechnet
10:15:33.81 CheckTmpStore
10:15:33.85 Importieren der SMS hat funktioniert...
10:15:33.85 Settimeout: RT=15000 WT=1000
10:15:33.85 [TX]: AT+CPMS="SM","SM"
10:15:33.95 [RX]: AT+CPMS="SM","SM"
10:15:33.95 [RX]: +CPMS: 0,20,0,20,141,170
10:15:33.96 [RX]: OK
10:15:33.96 [TX]: AT+CMGL=4
10:15:34.07 [RX]: AT+CMGL=4
10:15:34.07 [RX]: OK
10:15:34.07 CheckTmpStore
10:15:34.09 ErrMsg: C:\Documents and Settings\Mille\Application Data\MyPhoneExplorer\Sony Ericsson K608i [3568420012xxxxx]\SMS.dat
could not be created!
10:16:28.93 SMS-Datenbank gespeichert. Dauer:54844 SMS:136
10:16:29.12 [TX]: AT*ECAM=1
10:16:29.18 [RX]: AT*ECAM=1
10:16:29.18 [RX]: OK
10:16:37.90 Settimeout: RT=1500 WT=800
10:16:37.90 [TX]: AT+CBC
10:16:37.96 [RX]: AT+CBC
10:16:37.96 [RX]: +CBC: 1, 100
10:16:37.98 [RX]: OK
10:16:37.98 [TX]: AT+CSQ
10:16:38.04 [RX]: AT+CSQ
10:16:38.04 [RX]: +CSQ: 99,99
10:16:38.07 [RX]: OK