Dmc100v/dialog 112 communication error HEELP

The machine is programmed with cam, custom manufacturing from small several line drilling/milling programs to a 500k+ lines complex 3d programs. Recently we got more and more 3d stuff, and the machine starts throwing error after random time of run. Sometimes twice a day, sometimes 10x a day (usually near the end of the finishing process lol). The error code is : P461 file i/o error 65535 0. When this happens, the machine just stops moving, except the spindle and the coolant. The tool just rotates forever in place. This occours usually during long programs, but happened already during short drill program too... If i restart, then usually complete the program without error. Communication is going with ftp server. I used a dedicated windows pc with filezilla ftp server, but recently replaced the pc with an openwrt routers ftp server. Works well, but its making the same io error thing. I changed the utp cable too, but no luck. Any help would be appreciate.