landsteinar and navision 3.60

i am using navision 3.60 with sql server and a number of about 70 pos i use landsteinar data director to collect the transaction. i use 10 transaction server for the job, but for about 10 days now the pos are stucking in sending transactions for some tiem and then become ready and this happens all the time.In the server in the event viewer i found the following messages "hanging aplication finsql.exe ver 3.60 hang module hungapp,version hung address 0x00000000" and an other one "executestm-error in execute update. your activity was deadlocked with another user modifying the (symbols) table any sugestions? if the is a better way to setup the communications of the pos with the server just tell me. thanks