Usolve bug?

[tdh79]

I don't know how many of you guys use the Usolve app but I'm gonna try asking for som input anyway..
I succesfully created a directory with equations and variables for Linear Motion in physics so i believe I must be doing something right.
My problem is when i try to make a new one for electric voltage, currents etc..
The set of EQs is as follows:
P=U*I
U=I*R
E=U*I*t

Variables in these EQs:
P=Power, unit=W
I=Current, unit=A
E=Energy, unit=Ws (watt seconds)
R=Resistance, unit=Ω
t=Time, unit=s

My problem is that this set works fine until i set any of the units. If I leave all units blank the it will solve for all values without issue, if i set any of the units the i get Error: Bad Guess(es).
If I leave out the EQ for Energy the it all works fine with all the units set.

These formulas may seem a little off since I use Norwegian names..