so we have a machine with mach3 with dual head 2 spindels (we made the machine and put the setting for  the mach3 )
tool 1 is g54 offset and tool 2  is g55 offset good .
first i define  the offset for each tool 
2 .start the job with tool1
3. a tool change command  in the gcode file is send
4.machine move to the second  tool offset and start working normal 
5.now if i press pause button and then press start .problem happen now
so the assume it self in g54 and move to the current line position but in g54 offset. (part origin = x=0,y=0 and lets g54 is offset  x=0,y=0 and g55 offset is x=15,y=0 , and current line is go to position x=100 so it will move to position x=100 not 115 )
so can any one help

I would look at using G52 and forget about using G55.

G52 is active until cancelled with G52 X0 Y0

Example

%
#100 = 15. (X offset T2)
#101 = 0    (Y offset T2)

T1 M6
G52 X0 Y0
G00 X0 Y0
....
(rest of tool 1)

T2 M6
G52 X#100 Y#101
G00 X0 Y0
etc...
(end of tool 2)
G52 X0 Y0
M30
%