This error usually happens if one of your scripts uses an excessive number of CPU cycles.
Please check out
http://x10hosting.com/wiki/High_Resource_Usage.
At present you are allowed 300 CPU seconds per hour. 1 second of CPU time means you used a
full core (2.93Ghz) for the
whole second. For clarity, if you use 293Mhz for 10 seconds it would equal 1 second of CPU time. Small websites aren't usually that resource intensive and as such, this limit does actually only affect high CPU users.
Unfortunately, that seems to include you!
The way to get around it without changing your scripts would involve upgrading your account. Check out
x10Premium.com if that's an avenue you'd like to explore.